MadSci Network: Neuroscience

Re: what are the purposes of THC receptors

Date: Wed Oct 11 15:07:14 2000
Posted By: Gabriel Vargas M.D.,Ph.D., Post-doc/Fellow, Neurosciences/Psychiatry
Area of science: Neuroscience
ID: 971245194.Ns

In answer to your questions in brief:
1.	Yes THC receptors do exist in the brain and
2.	They do have a purpose other than binding to THC, which is only 
found in Marijuana.  
What follows is a short discussion on this topic (modified from an online 
site on the effects of Marijuana).

The THC or cannabinoid receptor is a typical member of the largest known 
family of receptors: the G-protein-coupled receptors with their distinctive 
pattern in which the receptor molecule spans the cell membrane seven 
times.THC receptors are very abundant in the brain. 

 The Endogenous Cannabinoid System

For any drug for which there is a receptor, the logical question is, "Why 
does this receptor exist?" The short answer is that there is probably an 
endogenous agonist (that is, a compound that is naturally produced in the 
brain) that acts on  that receptor. The long answer begins with a search 
for such compounds in  the area of the body that produce the receptors and 
ends with a  determination of the natural function of those compounds. So 
far, the search has yielded several endogenous compounds that bind 
selectively to  cannabinoid receptors. The best studied of them are 
anandamide and  arachidonyl glycerol.  However, their physiological roles 
are not yet known.


The first endogenous cannabinoid to be discovered was 
arachidonylethanolamine, named anandamide from the Sanskrit word ananda, 
meaning "bliss." Anandamide appears to have both central (in the brain) and 
peripheral (in the rest of the body) effects. The precise neuroanatomical 
localization of anandamide and its function are not yet known. 

hope this helps,
gabriel vargas md/phd

Abood ME, Martin BR. 1996. Molecular neurobiology of the cannabinoid 
receptor. International Review of Neurobiology 39:197-221.

Calignano A, La Rana G. Giuffrida A, Piomelli D. 1998. Control of pain 
initiation by endogenous cannabinoids. Nature 394:277-281.

Childers SR, Breivogel CS. 1998. Cannabis and endogenous cannabinoid 
systems. Drug and Alcohol Dependence 51:173-187.

Devane WA, Hanus L, Breuer A, Pertwee RG, Stevenson LA, Griffing F. Gibson 
D, Mandelbaum A, Etinger A, Mechoulam R. 1992. Isolation and structure of a
brain constituent that binds to the cannabinoid receptor. Science 258: 
1946- 1949.

Dewey WL. 1986. Cannabinoid pharmacology. Pharmacology Review 38:151-178.

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