Metachlorophenylpiperazine (m-CPP) induced intracavernous pressure responses in anaesthetized rats.
Here we have recorded the effects of metachlorophenylpiperazine (m-CPP) on intracavernous pressure (ICP) in anesthetized rats pretreated with various pharmacological agents in an attempt to determine the mechanism and relevance of the m-CPP induced ICP response to other models of erection. m-CPP elicited consistent and significantly greater increases in ICP (71.5+/-6.6 mmHg) compared with the mixed 5-HT(2a/2c) agonists trifluoromethylphenylpiperazine (3.4+/-1.3 mmHg) and quipazine (10.9+/-1.8 mmHg). Blockade of 5-HT(2a) receptors with ketanserin failed to unmask any stimulatory effect of quipazine (7.2+/-1.0 mmHg). m-CPP induced ICP responses (71+/-7.0 mmHg) were unaffected in the presence of mianserin (63+/-5 mmHg) and ketanserin (51+/-12 mmHg). Spiperone significantly reduced the m-CPP induced increase in ICP (8.0+/-1.0 mmHg). Naloxone, yohimbine and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OHDPAT) failed to elicit increases in ICP on their own. All three drugs significantly reduced the latency to the first m-CPP induced ICP response compared to saline. Yohimbine increased the duration of m-CPP induced ICP responses whereas 8-OHDPAT increased the mean number of m-CPP induced ICP responses compared to saline. The effects of m-CPP on ICP in anesthetized rats may not be mediated by 5-HT(2c) receptors and appears to be similar to erection in copula, but not erection elicited by other drugs or penile sheath retraction.
Hayes
E S
ES
Department of Obstetrics and Gynaecology, the National University of Singapore, Singapore. ehayes@bart.rprc.washington.edu
Adaikan
P G
PG
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000758:Anesthesia; D000818:Animals; D008297:Male; D010410:Penile Erection / Q000187:drug effects*; D010413:Penis / Q000187:drug effects* / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D011312:Pressure; D011814:Quipazine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D012726:Sexual Behavior, Animal / Q000187:drug effects
D010879:Piperazines; D017366:Serotonin Receptor Agonists; C018406:1-(3-trifluoromethylphenyl)piperazine; D011814:Quipazine; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C015068:1-(3-chlorophenyl)piperazine