|
Neuropharmacology is the study of drugs which affect the central nervous system. These include psychotropic drugs that affect mood and behavior, anesthetics, sedatives, analgesics, anticonvulsants, narcotics, hypnotics and a variety of other substances. While the precise mechanism of action is unknown for most of these drugs, a large number of neuropharmacological agents appear to be involved primarily with synaptic events. The Department of Pharmacology and Experimental Therapeutics (DPET) contains a core group of investigators who study neuroactive compounds at the molecular, cellular and behavioral level. |
Psychopharmacology is the study of the effects of drugs on behavior, combining methods of psychology and pharmacology. Psychopharmacologists carryout their duties within a number of different settings, including academia, government, private research, industry and clinic. The study of the effects of drugs on behavior has been productively examined in human as well as nonhuman populations, both within and outside the laboratory. The central theme running through the research in this division is the use of behavioral principles as they interact with the effects of pharmacological agents and environmental events. |
|
Source: Tufts University School of Medicine's Department of Pharmacology and Experimental Therapeutics |
Source: American Psychological Association |
Plants with stimulant effects are among the earliest plants used by humankind for psychoactive effects. Our interest in them is due to their profound effect on mental functioning, increasing alertness, the ability to sustain effort, and in some cases, the induction of euphoria. Despite their seclusion to a particular geographic region, stimulant plants are widely used across the planet. A sizable portion of the world’s population regularly consumes tobacco, coffee, tea, or some other form of stimulant plants on a daily basis.
The stimulant plants are organized here (see the chart below) by their predominant neuro-chemical mechanism: purinergic (coffee, tea, cocoa, mate, guarana, and kola), cholinergic (tobacco, areca, and lobelia), and monoaminergic (ephedra, coca, and khat). It is worthwhile to note that most of these plant drugs work through neuromodulatory systems. They mostly create stimulation not through direct neuronal excitation, but rather by a modulation of neuronal activity. On the other hand, drugs that directly stimulate excitatory amino acids or block inhibitory amino acids more often have excitotoxic or convulsive effects (e.g., strychnine from Strychnos nux-vomica, or ibotenate from Amanita muscaria). Rather, the stimulant plants generally act through neuromodulatory receptors linked to G-proteins and intracellular messengers.
Several synthetic stimulants have been developed for clinical use or illegal trade. Amphetamine was synthesized in 1887, but its medical applications were not investigated until the 1920s (Rudgley 1999). It was first marketed in 1932 as a treatment for asthma and nasal congestion. Since then, a number of related drugs have been developed. Methylphenidate (Ritalin) and pemoline (Cylert) have generally replaced amphetamines for treatment of attention disorders. Methylenedioxymethamphetamine (MDMA, “Ecstasy”) and several other amphetamine derivatives have been labeled “entactogens,” due to their prominent effect of creating feelings of interpersonal warmth and empathy. They are also highly neurotoxic to serotonin neurons (White et al. 1996). Amphetamines and related drugs have long been used to reduce appetite and weight, but dependence liability, toxicity, and the tendency for rebound weight gain after drug discontinuation have made them impractical for this purpose. Despite the development of numerous synthetic stimulants, the use of plants or plant-derived drugs probably still accounts for the majority of human stimulant consumption.
Purinergic Stimulants
The purinergic stimulants are a small group of chemically and pharmacologically related drugs that are found in several different plants but commonly act on purine neurotransmitters such as adenosine. Namely, the drugs are caffeine, theophylline, and theobromine, collectively referred to as the methylxanthines. They are among the most commonly used stimulants in the world, and possibly the most commonly consumed of all drugs. Methylxanthines are found in several plants that are well known across the world, and in others whose use is more regional. Collectively, these plants include coffee, cocoa, guarana, mate, and kola.
Central nervous system stimulants
Common |
Botanical |
Active constituents |
Mechanism |
|
Purinergic |
|
||
|
Coffee |
Coffea arabica |
Methylxanthines |
Adenosine antagonism |
|
Tea |
Camellia sinensis |
||
|
Cocoa |
Theobroma cacao |
||
|
Guarana |
Paullinia cupana |
||
|
Maté |
Ilex paraguariensis |
||
|
Kola |
Cola nitida & acuminata |
||
|
|
|||
|
Cholinergic |
|
||
|
Tobacco |
Nicotiana tobacum |
Nicotine |
Nicotinic Ach agonist |
|
Areca |
Areca cathechu |
Arecoline, arecaidine, guvacoline guvacine |
Muscarinic Ach agonist |
|
Lobelia |
Lobelia inflata |
Lobeline |
Nicotinic Ach agonist |
|
|
|||
|
Monoaminergic |
|
||
|
Ephedra |
Ephedra sinica |
Ephedrine |
α, β adrenergic agonist Blocks monoamine reuptake Na+ channel antagonist |
|
Khat |
Catha edulis |
Cathinone |
Source: The Psychopharmacology of Herbal Medicine, by Marcello Spinella
RELATED ORGANIZATIONS
|
American College of Clinical Pharmacology (ACCP) 3 Ellinwood Ct. New Hartford NY 13413-1105 Phone: (315) 768-6117 Fax: (315) 768-6119 Email: http://www.accp1.org/ |
American College of Neuropharmacology (ACNP) ACNP Secretariat 320 Centre Building 2014 Broadway Nashville, TN 37203 Phone: (615) 322-2075 Fax: (615) 343-0662 E-Mail: http://www.acnp.org/ |
American Psychological Association Division of Psychopharmacology and Substance Abuse 750 First Street, NE Washington, DC 20002-4242 Phone: (800) 374-2721; 202-336-5510 TDD/TTY: 202-336-6123 Email: http://www.apa.org/divisions/div28/index.html |
|
American Society for Pharmacology and Experimental Therapeutics (ASPET) 9650 Rockville Pike Bethesda, MD 20814-3995 Phone: (301) 634-7060 Fax: (301) 634-7061 Email: http://www.aspet.org/ |
Federation of American Societies for Experimental Biology (FASEB) 9650 Rockville Pike Bethesda, Maryland 20814-3998 Phone (301) 530-7000 Fax (301) 530-7001 Email: http://www.faseb.org |
Food and Drug Administration Center for Drug Evaluation and Research Program and Speaker Coordination Staff 5600 Fishers Lane, Room 15A-08 Rockville, MD 20857 Phone: (301) 827-4573 Fax: 301-827-2823 Email: http://www.fda.gov/cder/drug/default.htm |
|
National Clearinghouse for Alcohol and Drug Information 11426-28 Rockville Pike, Suite 200 Rockville, MD 20852 Phone: (800) 729-6686 Fax: (301) 468-6433 Email: http://www.health.org/ |
Society for Neuroscience 11 Dupont Circle, N.W., Suite 500 Washington D.C. 20036 Phone: (202) 462-6688 Fax: (202) 462-9740 Email: http://www.sfn.org/ |
U.S. National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894 Phone: (888) 346-3656 or (301) 594-5983 (local and international calls) Fax: 301-496-4450 Email: http://www.nlm.nih.gov/ |
USEFUL WEBSITES
PubMed, a service of the National Library of Medicine, provides access to over 11 million MEDLINE citations back to the mid-1960's and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
Neurosciences on the Internet, a searchable and browsable index of neuroscience resources available on the Internet: Neurobiology, neurology, neurosurgery, psychiatry, psychology, cognitive science sites and information on human neurological diseases.