Author: M. O. Faruk Khan
Publisher: Bentham Science Publishers
ISBN: 1681086875
Category : Medical
Languages : en
Pages : 349
Book Description
The primary objective of this 4-volume book series is to educate PharmD students on the subject of medicinal chemistry. The book set serves as a reference guide to pharmacists on aspects of chemical basis of drug action. This first volume of the series is comprised of 8 chapters focusing on basic background information about medicinal chemistry. It takes a succinct and conceptual approach to introducing important fundamental concepts required for a clear understanding of various facets of pharmacotherapeutic agents, drug metabolism and important biosynthetic pathways that are relevant to drug action. Notable topics covered in this first volume include the scope and importance of medicinal chemistry in pharmacy education, a comprehensive discussion of the organic functional groups present in drugs, and information about four major types of biomolecules (proteins, carbohydrates, lipids, nucleic acids) and key heterocyclic ring systems. The concepts of acid-base chemistry and salt formation, and their applications to the drug action and design follow thereafter. These include concepts of solubility and lipid-water partition coefficient (LWPC), isosterism, stereochemical properties, mechanisms of drug action, drug receptor interactions critical for pharmacological responses of drugs, and much more. Students and teachers will be able to integrate the knowledge presented in the book and apply medicinal chemistry concepts to understand the pharmacodynamics and pharmacokinetics of therapeutic agents in the body.
Fundamentals of Medicinal Chemistry and Drug Metabolism
Author: M. O. Faruk Khan
Publisher: Bentham Science Publishers
ISBN: 1681086875
Category : Medical
Languages : en
Pages : 349
Book Description
The primary objective of this 4-volume book series is to educate PharmD students on the subject of medicinal chemistry. The book set serves as a reference guide to pharmacists on aspects of chemical basis of drug action. This first volume of the series is comprised of 8 chapters focusing on basic background information about medicinal chemistry. It takes a succinct and conceptual approach to introducing important fundamental concepts required for a clear understanding of various facets of pharmacotherapeutic agents, drug metabolism and important biosynthetic pathways that are relevant to drug action. Notable topics covered in this first volume include the scope and importance of medicinal chemistry in pharmacy education, a comprehensive discussion of the organic functional groups present in drugs, and information about four major types of biomolecules (proteins, carbohydrates, lipids, nucleic acids) and key heterocyclic ring systems. The concepts of acid-base chemistry and salt formation, and their applications to the drug action and design follow thereafter. These include concepts of solubility and lipid-water partition coefficient (LWPC), isosterism, stereochemical properties, mechanisms of drug action, drug receptor interactions critical for pharmacological responses of drugs, and much more. Students and teachers will be able to integrate the knowledge presented in the book and apply medicinal chemistry concepts to understand the pharmacodynamics and pharmacokinetics of therapeutic agents in the body.
Publisher: Bentham Science Publishers
ISBN: 1681086875
Category : Medical
Languages : en
Pages : 349
Book Description
The primary objective of this 4-volume book series is to educate PharmD students on the subject of medicinal chemistry. The book set serves as a reference guide to pharmacists on aspects of chemical basis of drug action. This first volume of the series is comprised of 8 chapters focusing on basic background information about medicinal chemistry. It takes a succinct and conceptual approach to introducing important fundamental concepts required for a clear understanding of various facets of pharmacotherapeutic agents, drug metabolism and important biosynthetic pathways that are relevant to drug action. Notable topics covered in this first volume include the scope and importance of medicinal chemistry in pharmacy education, a comprehensive discussion of the organic functional groups present in drugs, and information about four major types of biomolecules (proteins, carbohydrates, lipids, nucleic acids) and key heterocyclic ring systems. The concepts of acid-base chemistry and salt formation, and their applications to the drug action and design follow thereafter. These include concepts of solubility and lipid-water partition coefficient (LWPC), isosterism, stereochemical properties, mechanisms of drug action, drug receptor interactions critical for pharmacological responses of drugs, and much more. Students and teachers will be able to integrate the knowledge presented in the book and apply medicinal chemistry concepts to understand the pharmacodynamics and pharmacokinetics of therapeutic agents in the body.
Fundamentals of Medicinal Chemistry
Author: Gareth Thomas
Publisher: John Wiley & Sons
ISBN: 0470871695
Category : Science
Languages : en
Pages : 302
Book Description
Provides a concise introduction to the chemistry of therapeutically active compounds, written in a readable and accessible style. The title begins by reviewing the structures and nomenclature of the more common classes of naturally occurring compounds found in biological organisms. An overview of medicinal chemistry is followed by chapters covering the discovery and design of drugs, pharmacokinetics and drug metabolism, The book concludes with a chapter on organic synthesis, followed by a brief look at drug development from the research stage through to marketing the final product. The text assumes little in the way of prior biological knowledge. relevant biology is included through biological topics, examples and the Appendices. Incorporates summary sections, examples, applications and problems Each chapter contains an additional summary section and solutions to the questions are provided at the end of the text Invaluable for undergraduates studying within the chemical, pharmaceutical and life sciences.
Publisher: John Wiley & Sons
ISBN: 0470871695
Category : Science
Languages : en
Pages : 302
Book Description
Provides a concise introduction to the chemistry of therapeutically active compounds, written in a readable and accessible style. The title begins by reviewing the structures and nomenclature of the more common classes of naturally occurring compounds found in biological organisms. An overview of medicinal chemistry is followed by chapters covering the discovery and design of drugs, pharmacokinetics and drug metabolism, The book concludes with a chapter on organic synthesis, followed by a brief look at drug development from the research stage through to marketing the final product. The text assumes little in the way of prior biological knowledge. relevant biology is included through biological topics, examples and the Appendices. Incorporates summary sections, examples, applications and problems Each chapter contains an additional summary section and solutions to the questions are provided at the end of the text Invaluable for undergraduates studying within the chemical, pharmaceutical and life sciences.
Basic Concepts in Medicinal Chemistry
Author: Marc Harrold
Publisher: ASHP
ISBN: 1585283649
Category : Medical
Languages : en
Pages : 405
Book Description
Medicinal chemistry is a complex topic. Written in an easy to follow and conversational style, Basic Concepts in Medicinal Chemistry focuses on the fundamental concepts that govern the discipline of medicinal chemistry as well as how and why these concepts are essential to therapeutic decisions. The book emphasizes functional group analysis and the basics of drug structure evaluation. In a systematic fashion, learn how to identify and evaluate the functional groups that comprise the structure of a drug molecule and their influences on solubility, absorption, acid/base character, binding interactions, and stereochemical orientation. Relevant Phase I and Phase II metabolic transformations are also discussed for each functional group. Key features include: • Discussions on the roles and characteristics of organic functional groups, including the identification of acidic and basic functional groups. • How to solve problems involving pH, pKa, and ionization; salts and solubility; drug binding interactions; stereochemistry; and drug metabolism. • Numerous examples and expanded discussions for complex concepts. • Therapeutic examples that link the importance of medicinal chemistry to pharmacy and healthcare practice. • An overview of structure activity relationships (SARs) and concepts that govern drug design. • Review questions and practice problems at the end of each chapter that allow readers to test their understanding, with the answers provided in an appendix. Whether you are just starting your education toward a career in a healthcare field or need to brush up on your organic chemistry concepts, this book is here to help you navigate medicinal chemistry. About the Authors Marc W. Harrold, BS, Pharm, PhD, is Professor of Medicinal Chemistry at the Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA. Professor Harrold is the 2011 winner of the Omicron Delta Kappa "Teacher of the Year" award at Duquesne University. He is also the two-time winner of the "TOPS" (Teacher of the Pharmacy School) award at the Mylan School of Pharmacy. Robin M. Zavod, PhD, is Associate Professor for Pharmaceutical Sciences at the Chicago College of Pharmacy, Midwestern University, Downers Grove, IL, where she was awarded the 2012 Outstanding Faculty of the Year award. Professor Zavod also serves on the adjunct faculty for Elmhurst College and the Illinois Institute of Technology. She currently serves as Editor-in-Chief of the journal Currents in Pharmacy Teaching and Learning.
Publisher: ASHP
ISBN: 1585283649
Category : Medical
Languages : en
Pages : 405
Book Description
Medicinal chemistry is a complex topic. Written in an easy to follow and conversational style, Basic Concepts in Medicinal Chemistry focuses on the fundamental concepts that govern the discipline of medicinal chemistry as well as how and why these concepts are essential to therapeutic decisions. The book emphasizes functional group analysis and the basics of drug structure evaluation. In a systematic fashion, learn how to identify and evaluate the functional groups that comprise the structure of a drug molecule and their influences on solubility, absorption, acid/base character, binding interactions, and stereochemical orientation. Relevant Phase I and Phase II metabolic transformations are also discussed for each functional group. Key features include: • Discussions on the roles and characteristics of organic functional groups, including the identification of acidic and basic functional groups. • How to solve problems involving pH, pKa, and ionization; salts and solubility; drug binding interactions; stereochemistry; and drug metabolism. • Numerous examples and expanded discussions for complex concepts. • Therapeutic examples that link the importance of medicinal chemistry to pharmacy and healthcare practice. • An overview of structure activity relationships (SARs) and concepts that govern drug design. • Review questions and practice problems at the end of each chapter that allow readers to test their understanding, with the answers provided in an appendix. Whether you are just starting your education toward a career in a healthcare field or need to brush up on your organic chemistry concepts, this book is here to help you navigate medicinal chemistry. About the Authors Marc W. Harrold, BS, Pharm, PhD, is Professor of Medicinal Chemistry at the Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA. Professor Harrold is the 2011 winner of the Omicron Delta Kappa "Teacher of the Year" award at Duquesne University. He is also the two-time winner of the "TOPS" (Teacher of the Pharmacy School) award at the Mylan School of Pharmacy. Robin M. Zavod, PhD, is Associate Professor for Pharmaceutical Sciences at the Chicago College of Pharmacy, Midwestern University, Downers Grove, IL, where she was awarded the 2012 Outstanding Faculty of the Year award. Professor Zavod also serves on the adjunct faculty for Elmhurst College and the Illinois Institute of Technology. She currently serves as Editor-in-Chief of the journal Currents in Pharmacy Teaching and Learning.
Drug Metabolism and Pharmacokinetics Quick Guide
Author: Siamak Cyrus Khojasteh
Publisher: Springer Science & Business Media
ISBN: 1441956298
Category : Medical
Languages : en
Pages : 222
Book Description
Drug Metabolism and Pharmacokinetics Quick Guide covers a number of aspects of drug assessment at drug discovery and development stages, topics such as pharmacokinetics, absorption, metabolism, enzyme kinetics, drug transporters, drug interactions, drug-like properties, assays and in silico calculations. It covers key concepts, with useful tables on physiological parameters (eg. blood flow to organs in x-species, expression and localization of enzymes and transporters), chemical structure, nomenclature, and moieties leading to bioactivation (with examples). Overall it includes a number of key topics useful at the drug discovery stage, which would serve as a quick reference with several examples from the literature to illustrate the concept.
Publisher: Springer Science & Business Media
ISBN: 1441956298
Category : Medical
Languages : en
Pages : 222
Book Description
Drug Metabolism and Pharmacokinetics Quick Guide covers a number of aspects of drug assessment at drug discovery and development stages, topics such as pharmacokinetics, absorption, metabolism, enzyme kinetics, drug transporters, drug interactions, drug-like properties, assays and in silico calculations. It covers key concepts, with useful tables on physiological parameters (eg. blood flow to organs in x-species, expression and localization of enzymes and transporters), chemical structure, nomenclature, and moieties leading to bioactivation (with examples). Overall it includes a number of key topics useful at the drug discovery stage, which would serve as a quick reference with several examples from the literature to illustrate the concept.
Bioinorganic Medicinal Chemistry
Author: Enzo Alessio
Publisher: John Wiley & Sons
ISBN: 352763312X
Category : Science
Languages : en
Pages : 625
Book Description
This book gives a comprehensive overview about medicinal inorganic chemistry. Topics like targeting strategies, mechanism of action, Pt-based antitumor drugs, radiopharmaceuticals are covered in detail and offer the reader an in-depth overview about this important topic.
Publisher: John Wiley & Sons
ISBN: 352763312X
Category : Science
Languages : en
Pages : 625
Book Description
This book gives a comprehensive overview about medicinal inorganic chemistry. Topics like targeting strategies, mechanism of action, Pt-based antitumor drugs, radiopharmaceuticals are covered in detail and offer the reader an in-depth overview about this important topic.
Medicinal Chemistry
Author: Roland Barret
Publisher: Elsevier
ISBN: 0081027605
Category : Technology & Engineering
Languages : en
Pages : 174
Book Description
Medicinal Chemistry: Fundaments presents the cycle of the life of drugs, their physico-chemical properties, and consequences that arise in development. The fundamental concepts of Medicinal Chemistry (pharmacophore, prodrugs, Lipinsky rules) are also presented, including discussions on specific concerns of the European Pharmacopeia – the industrialist's bible – its role, and a description of the monographs of active principles. - Defines the lifecycle of drugs - Explains the physico-chemical properties and consequences of a drug - Studies the fundamental concepts of medicinal chemistry - Describes the active ingredient monographs
Publisher: Elsevier
ISBN: 0081027605
Category : Technology & Engineering
Languages : en
Pages : 174
Book Description
Medicinal Chemistry: Fundaments presents the cycle of the life of drugs, their physico-chemical properties, and consequences that arise in development. The fundamental concepts of Medicinal Chemistry (pharmacophore, prodrugs, Lipinsky rules) are also presented, including discussions on specific concerns of the European Pharmacopeia – the industrialist's bible – its role, and a description of the monographs of active principles. - Defines the lifecycle of drugs - Explains the physico-chemical properties and consequences of a drug - Studies the fundamental concepts of medicinal chemistry - Describes the active ingredient monographs
Introductory Medicinal Chemistry
Author: J. B. Taylor
Publisher: Halsted Press
ISBN: 9780470201374
Category : Pharmaceutical chemistry
Languages : en
Pages : 202
Book Description
Publisher: Halsted Press
ISBN: 9780470201374
Category : Pharmaceutical chemistry
Languages : en
Pages : 202
Book Description
Basic Principles of Drug Discovery and Development
Author: Benjamin E. Blass
Publisher: Academic Press
ISBN: 0128172150
Category : Science
Languages : en
Pages : 738
Book Description
Basic Principles of Drug Discovery and Development presents the multifaceted process of identifying a new drug in the modern era, which requires a multidisciplinary team approach with input from medicinal chemists, biologists, pharmacologists, drug metabolism experts, toxicologists, clinicians, and a host of experts from numerous additional fields. Enabling technologies such as high throughput screening, structure-based drug design, molecular modeling, pharmaceutical profiling, and translational medicine are critical to the successful development of marketable therapeutics. Given the wide range of disciplines and techniques that are required for cutting edge drug discovery and development, a scientist must master their own fields as well as have a fundamental understanding of their collaborator's fields. This book bridges the knowledge gaps that invariably lead to communication issues in a new scientist's early career, providing a fundamental understanding of the various techniques and disciplines required for the multifaceted endeavor of drug research and development. It provides students, new industrial scientists, and academics with a basic understanding of the drug discovery and development process. The fully updated text provides an excellent overview of the process and includes chapters on important drug targets by class, in vitro screening methods, medicinal chemistry strategies in drug design, principles of in vivo pharmacokinetics and pharmacodynamics, animal models of disease states, clinical trial basics, and selected business aspects of the drug discovery process. - Provides a clear explanation of how the pharmaceutical industry works, as well as the complete drug discovery and development process, from obtaining a lead, to testing the bioactivity, to producing the drug, and protecting the intellectual property - Includes a new chapter on the discovery and development of biologics (antibodies proteins, antibody/receptor complexes, antibody drug conjugates), a growing and important area of the pharmaceutical industry landscape - Features a new section on formulations, including a discussion of IV formulations suitable for human clinical trials, as well as the application of nanotechnology and the use of transdermal patch technology for drug delivery - Updated chapter with new case studies includes additional modern examples of drug discovery through high through-put screening, fragment-based drug design, and computational chemistry
Publisher: Academic Press
ISBN: 0128172150
Category : Science
Languages : en
Pages : 738
Book Description
Basic Principles of Drug Discovery and Development presents the multifaceted process of identifying a new drug in the modern era, which requires a multidisciplinary team approach with input from medicinal chemists, biologists, pharmacologists, drug metabolism experts, toxicologists, clinicians, and a host of experts from numerous additional fields. Enabling technologies such as high throughput screening, structure-based drug design, molecular modeling, pharmaceutical profiling, and translational medicine are critical to the successful development of marketable therapeutics. Given the wide range of disciplines and techniques that are required for cutting edge drug discovery and development, a scientist must master their own fields as well as have a fundamental understanding of their collaborator's fields. This book bridges the knowledge gaps that invariably lead to communication issues in a new scientist's early career, providing a fundamental understanding of the various techniques and disciplines required for the multifaceted endeavor of drug research and development. It provides students, new industrial scientists, and academics with a basic understanding of the drug discovery and development process. The fully updated text provides an excellent overview of the process and includes chapters on important drug targets by class, in vitro screening methods, medicinal chemistry strategies in drug design, principles of in vivo pharmacokinetics and pharmacodynamics, animal models of disease states, clinical trial basics, and selected business aspects of the drug discovery process. - Provides a clear explanation of how the pharmaceutical industry works, as well as the complete drug discovery and development process, from obtaining a lead, to testing the bioactivity, to producing the drug, and protecting the intellectual property - Includes a new chapter on the discovery and development of biologics (antibodies proteins, antibody/receptor complexes, antibody drug conjugates), a growing and important area of the pharmaceutical industry landscape - Features a new section on formulations, including a discussion of IV formulations suitable for human clinical trials, as well as the application of nanotechnology and the use of transdermal patch technology for drug delivery - Updated chapter with new case studies includes additional modern examples of drug discovery through high through-put screening, fragment-based drug design, and computational chemistry
Burger's Medicinal Chemistry, Drug Discovery and Development, 8 Volume Set
Author:
Publisher: John Wiley & Sons
ISBN: 111953030X
Category : Science
Languages : en
Pages : 6057
Book Description
Burger’s Medicinal Chemistry, Drug Discovery and Development Explore the freshly updated flagship reference for medicinal chemists and pharmaceutical professionals The newly revised eighth edition of the eight-volume Burger’s Medicinal Chemistry, Drug Discovery and Development is the latest installment in this celebrated series covering the entirety of the drug development and discovery process. With the addition of expert editors in each subject area, this eight-volume set adds 35 chapters to the extensive existing chapters. New additions include analyses of opioid addiction treatments, antibody and gene therapy for cancer, blood-brain barrier, HIV treatments, and industrial-academic collaboration structures. Along with the incorporation of practical material on drug hunting, the set features sections on drug discovery, drug development, cardiovascular diseases, metabolic diseases, immunology, cancer, anti-Infectives, and CNS disorders. The text continues the legacy of previous volumes in the series by providing recognized, renowned, authoritative, and comprehensive information in the area of drug discovery and development while adding cutting-edge new material on issues like the use of artificial intelligence in medicinal chemistry. Included: Volume 1: Methods in Drug Discovery, edited by Kent D. Stewart Volume 2: Discovering Lead Molecules, edited by Kent D. Stewart Volume 3: Drug Development, edited by Ramnarayan S. Randad and Michael Myers Volume 4: Cardiovascular, Endocrine, and Metabolic Diseases, edited by Scott D. Edmondson Volume 5: Pulmonary, Bone, Immunology, Vitamins, and Autocoid Therapeutic Agents, edited by Bryan H. Norman Volume 6: Cancer, edited by Barry Gold and Donna M. Huryn Volume 7: Anti-Infectives, edited by Roland E. Dolle Volume 8: CNS Disorders, edited by Richard A. Glennon Perfect for research departments in the pharmaceutical and biotechnology industries, Burger’s Medicinal Chemistry, Drug Discovery and Development can be used by graduate students seeking a one-stop reference for drug development and discovery and deserves its place in the libraries of biomedical research institutes, medical, pharmaceutical, and veterinary schools.
Publisher: John Wiley & Sons
ISBN: 111953030X
Category : Science
Languages : en
Pages : 6057
Book Description
Burger’s Medicinal Chemistry, Drug Discovery and Development Explore the freshly updated flagship reference for medicinal chemists and pharmaceutical professionals The newly revised eighth edition of the eight-volume Burger’s Medicinal Chemistry, Drug Discovery and Development is the latest installment in this celebrated series covering the entirety of the drug development and discovery process. With the addition of expert editors in each subject area, this eight-volume set adds 35 chapters to the extensive existing chapters. New additions include analyses of opioid addiction treatments, antibody and gene therapy for cancer, blood-brain barrier, HIV treatments, and industrial-academic collaboration structures. Along with the incorporation of practical material on drug hunting, the set features sections on drug discovery, drug development, cardiovascular diseases, metabolic diseases, immunology, cancer, anti-Infectives, and CNS disorders. The text continues the legacy of previous volumes in the series by providing recognized, renowned, authoritative, and comprehensive information in the area of drug discovery and development while adding cutting-edge new material on issues like the use of artificial intelligence in medicinal chemistry. Included: Volume 1: Methods in Drug Discovery, edited by Kent D. Stewart Volume 2: Discovering Lead Molecules, edited by Kent D. Stewart Volume 3: Drug Development, edited by Ramnarayan S. Randad and Michael Myers Volume 4: Cardiovascular, Endocrine, and Metabolic Diseases, edited by Scott D. Edmondson Volume 5: Pulmonary, Bone, Immunology, Vitamins, and Autocoid Therapeutic Agents, edited by Bryan H. Norman Volume 6: Cancer, edited by Barry Gold and Donna M. Huryn Volume 7: Anti-Infectives, edited by Roland E. Dolle Volume 8: CNS Disorders, edited by Richard A. Glennon Perfect for research departments in the pharmaceutical and biotechnology industries, Burger’s Medicinal Chemistry, Drug Discovery and Development can be used by graduate students seeking a one-stop reference for drug development and discovery and deserves its place in the libraries of biomedical research institutes, medical, pharmaceutical, and veterinary schools.
Drug Discrimination
Author: Richard A. Glennon
Publisher: John Wiley & Sons
ISBN: 0470433523
Category : Medical
Languages : en
Pages : 534
Book Description
Drug discrimination: a practical guide to its contributions to the invention of new chemical entities and evaluations of new or known pharmacological agents Drug discrimination can be described as a "drug detection" procedure that uses a pharmacologically active agent as the subjective stimulus. Although the procedure does require some effort to implement, it can be an extremely important tool for understanding drug action. Whereas medicinal chemists should come to learn the types of information that drug discrimination studies can offer, pharmacologists and psychologists might come to realize how medicinal chemists can apply the types of information that the paradigm routinely provides. Drug Discrimination: Applications to Medicinal Chemistry and Drug Studies provides in-depth analyses of the nature and use of drugs as discriminative stimuli and bridges some of the numerous gaps between medicinal chemistry, pharmacology, and psychology. Stressing the practical aspects of drug discrimination, including types of procedures, study design, data, and interpretation, the book details the advantages and limitations of drug discrimination studies versus other pharmacologic evaluations. Practical information from leading researchers in the field addresses specific topics and techniques that are of interest in drug discovery, evaluation, and development. A groundbreaking new guide to the applications of drug discrimination studies for medicinal chemistry and neuroscience, Drug Discrimination is essential for any scientist, researcher, or student whose interests involve the design, development, and/or action of drugs acting at the level of the central nervous system.
Publisher: John Wiley & Sons
ISBN: 0470433523
Category : Medical
Languages : en
Pages : 534
Book Description
Drug discrimination: a practical guide to its contributions to the invention of new chemical entities and evaluations of new or known pharmacological agents Drug discrimination can be described as a "drug detection" procedure that uses a pharmacologically active agent as the subjective stimulus. Although the procedure does require some effort to implement, it can be an extremely important tool for understanding drug action. Whereas medicinal chemists should come to learn the types of information that drug discrimination studies can offer, pharmacologists and psychologists might come to realize how medicinal chemists can apply the types of information that the paradigm routinely provides. Drug Discrimination: Applications to Medicinal Chemistry and Drug Studies provides in-depth analyses of the nature and use of drugs as discriminative stimuli and bridges some of the numerous gaps between medicinal chemistry, pharmacology, and psychology. Stressing the practical aspects of drug discrimination, including types of procedures, study design, data, and interpretation, the book details the advantages and limitations of drug discrimination studies versus other pharmacologic evaluations. Practical information from leading researchers in the field addresses specific topics and techniques that are of interest in drug discovery, evaluation, and development. A groundbreaking new guide to the applications of drug discrimination studies for medicinal chemistry and neuroscience, Drug Discrimination is essential for any scientist, researcher, or student whose interests involve the design, development, and/or action of drugs acting at the level of the central nervous system.