Endogenous CART peptide regulates mu opioid and serotonin 5-HT(2A) receptors.
Previous experiments conducted in this laboratory showed that intracerebroventricular (i.c.v.) administration of IgG antibodies directed against selected neuropeptides changed the density of CNS receptors, suggesting that neuropeptides in the cerebrospinal fluid can perform a regulatory role. To further test this hypothesis, we administered anti-CART peptide (the peptide product of cocaine amphetamine related transcript) IgG to rats via the i.c.v. route, and measured the density of opioid mu and delta receptors, beta-adrenergic and alpha(2)-adrenergic receptors and serotonin 5-HT(2A) receptors using ligand binding methods. We also used Western blots to determine the expression level of the mu, delta and 5-HT(2A) receptors. The results demonstrated that anti-CART peptide IgG up-regulates mu and 5-HT(2A) receptor in the hippocampus and caudate We conclude that CART peptides in the cerebrospinal fluid may exert regulatory effects in the brain.
Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, PO Box 5180, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA. rrothman@intra.nida.nih.gov
Richard B
RB
Rothman
Nga
N
Vu
Xiaoying
X
Wang
Heng
H
Xu
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects; D007074:Immunoglobulin G / Q000494:pharmacology; D008297:Male; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000134:cerebrospinal fluid / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000037:antagonists & inhibitors / Q000134:cerebrospinal fluid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000378:metabolism*; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
D007074:Immunoglobulin G; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D017450:Receptors, Opioid, mu; D011985:Receptors, Serotonin; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein