Role of nitric oxide in penile erection and yawning induced by 5-HT1c receptor agonists in male rats.
The effect of the intracerebroventricular (i.c.v.) administration of NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine, two inhibitors of nitric oxide (NO) synthase, on penile erection and yawning induced by 1-(3-chlorophenyl)-piperazine (m-CPP)- and N-(3-trifluoromethylphenyl)-piperazine (TFMPP), two selective 5HT1c receptor agonists, was studied in male rats. Both NO synthase inhibitors (50-500 micrograms i.c.v.) prevented dose-dependently the behavioural responses induced by m-CPP (0.5 mg/kg s.c.) or by TFMPP (1 mg/kg s.c.), but NG-nitro-L-arginine methyl ester was about 4-5 times more potent than NG-monomethyl-L-arginine. The D-isomer of NG-monomethyl-L-arginine, which does not inhibit nitric oxide synthase, was ineffective. The inhibitory effect of NG-nitro-L-arginine methyl ester on m-CPP- and TFMPP-induced responses was prevented by the administration of L-arginine (1 mg i.c.v.). In contrast, NG-nitro-L-arginine methyl ester (20 micrograms) was ineffective when injected in the paraventricular nucleus of the hypothalamus, a brain area that plays a key role in the expression of these behavioural responses. m-CPP- and TFMPP-induced penile erection and yawning was prevented also by the i.c.v. administration of LY 83583 (50-200 micrograms) or methylene blue (50-400 micrograms), two inhibitors of guanylate cyclase but not by reduced hemoglobin (50-400 micrograms), a NO scavenger. The results suggest that central nitric oxide is involved in the expression of penile erection and yawning induced by 5-HT1c receptor agonists.
Melis
M R
MR
Bernard B. Brodie Department of Neuroscience, University of Cagliari, Italy.
Stancampiano
R
R
Argiolas
A
A
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D007267:Injections; D007276:Injections, Intraventricular; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase; D010286:Paraventricular Hypothalamic Nucleus; D010410:Penile Erection / Q000187:drug effects / Q000502:physiology*; D010879:Piperazines / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D015000:Yawning / Q000187:drug effects / Q000502:physiology*; D019323:omega-N-Methylarginine
D010879:Piperazines; D017366:Serotonin Receptor Agonists; C018406:1-(3-trifluoromethylphenyl)piperazine; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D006162:Guanylate Cyclase; C015068:1-(3-chlorophenyl)piperazine; D019331:NG-Nitroarginine Methyl Ester