Effect of 5-HT1C and 5-HT2 receptor stimulation on excessive grooming, penile erection and plasma oxytocin concentrations.
Serotonin (5-HT) receptor agonist-induced excessive grooming, penile erection and oxytocin secretion were studied in chronically cannulated freely moving rats. The 5-HT1C receptor agonist, m-chlorophenylpiperazine (m-CPP), which also binds to other 5-HT receptors, produced dose-dependent excessive grooming, penile erection and increases in circulating oxytocin concentrations. Maximal responses for excessive grooming and penile erection occurred at 0.3-0.6 mg/kg i.v. m-CPP. Higher doses (0.9-2.5 mg/kg i.v.) caused further increases in oxytocin concentrations, but attenuated both behavioral responses. All three responses to m-CPP (0.6 mg/kg) were attenuated by antagonists with high affinity for the 5-HT1C receptor site (mianserin, LY-53857 and metergoline), but not by the 5-HT2 receptor antagonist ketanserin. The 5-HT2/5-HT1C agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), increased plasma oxytocin concentrations only. After ketanserin pretreatment, DOI caused penile erection and diminished the oxytocin response. All responses to DOI were blocked completely by pretreatment with LY-53857 plus ketanserin. Excessive grooming and penile erection showed significant bimodal correlations with the oxytocin response. These data suggest that stimulation of 5-HT1C receptors induces excessive grooming, penile erection and increased oxytocin secretion. Stimulation of 5-HT2 receptors causes a further increase in plasma oxytocin concentration, but inhibits both behavioral responses.
Bagdy
G
G
Laboratory of Experimental Medicine, National Institute of Psychiatry and Neurology, Budapest, Hungary.
Kalogeras
K T
KT
Szemeredi
K
K
D000704:Analysis of Variance; D000818:Animals; D006120:Grooming / Q000187:drug effects* / Q000502:physiology; D008297:Male; D010121:Oxytocin / Q000097:blood*; D010410:Penile Erection / Q000187:drug effects* / Q000502:physiology; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D010121:Oxytocin