Direct evidence of facilitative actions of dopamine in the medial preoptic area on reflexive and noncontact erections in male rats.
OBJECTIVE
We examined the effects of alterations of the extracellular dopamine level in the medial preoptic area on 2 erectile contexts, namely reflexive and noncontact erections, in male rats.


METHODS
The extracellular dopamine level was measured in the medial preoptic area after administering the dopamine reuptake inhibitor bupropion hydrochloride (Sigma Chemical Co., St. Louis, Missouri) into the same area through a micro-dialysis tube. We measured the frequency and latency of reflexive erections, and the frequency of noncontact erection during infusion of bupropion.


RESULTS
Administration of 10 mM. bupropion was associated with significant elevation in the extracellular dopamine level in the medial preoptic area. Bupropion (1 mM.) and Ringer's solution did not induce significant alterations in dopamine in the medial preoptic area. The number of reflexive erections significantly increased and erection latency decreased during infusion of 10 mM. bupropion into the medial preoptic area. The number of noncontact erections was also increased by administering 10 mM. of drug.


CONCLUSIONS
The altered dopamine level in the medial preoptic area affected 2 distinct penile erectile contexts, suggesting that the dopamine levels in the medial preoptic area may be involved in the regulation of erection. These results may have important implications for the central regulation of penile erection.
Adachi
Hideki
H
Department of Urology, Sapporo Medical University School of Medicine S-1, W-16, Chuo-ku, Sapporo 060, Japan.
Sato
Yoshikazu
Y
Kato
Ryuichi
R
Hisasue
Shinichi
S
Suzuki
Kazuhiro
K
Masumori
Naoya
N
Itoh
Naoki
N
Tsukamoto
Taiji
T
D000818:Animals; D016642:Bupropion / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D007552:Isotonic Solutions / Q000494:pharmacology; D008297:Male; D010410:Penile Erection / Q000187:drug effects / Q000502:physiology*; D011301:Preoptic Area / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D000077331:Ringer's Solution
D018765:Dopamine Uptake Inhibitors; D007552:Isotonic Solutions; D016642:Bupropion; D000077331:Ringer's Solution; D004298:Dopamine