Male sexual behavior and catecholamine levels in the medial preoptic area and arcuate nucleus in middle-aged rats.
The correlation between male sexual behavior and catecholamine levels in the medial preoptic area (MPOA) and arcuate nucleus (ARN) was studied in middle-aged rats. Male rats (18-19 months) were assigned to three groups: (1) Group MIE, consisting of rats showing mounts, intromissions, and ejaculations; (2) Group MI, consisting of rats showing mounts and intromissions, but no ejaculation; and (3) Group NC, consisting of non-copulators showing no sexual behavior. Young adult rats (4-5 months) displaying complete copulatory behavior were used as the control group. Dopamine (DA) and norepinephrine (NE) tissue levels in the MPOA and ARN were measured by high pressure liquid chromatography with electrochemical detection. There were no differences between MIE rats and young controls in DA or NE tissue levels in these two brain areas. Furthermore, no differences were found between the MI and NC groups in DA or NE tissue levels in either the MPOA or ARN. DA tissue levels in the MPOA and ARN in the MI and NC groups were significantly lower than those in the MIE group. NE tissue levels in the MPOA of the NC group were significantly lower than those in the MIE group, but no differences in NE tissue levels in the ARN were seen between the four groups. These results suggest that, in male rats, complete male sexual performance is related to tissue levels of DA, but not of NE, in the MPOA and/or ARN. Furthermore, ejaculatory behavior might be associated with critical DA tissue levels in the MPOA and/or ARN in middle-aged rats.
Chen
Joyce C
JC
Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsinchu, Taiwan, ROC.
Tsai
Houng-Wei
HW
Yeh
Kuei-Ying
KY
Tai
Mei-Yun
MY
Tsai
Yuan-Feen
YF
D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000502:physiology*; D001522:Behavior, Animal; D002395:Catecholamines / Q000378:metabolism*; D008297:Male; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D012726:Sexual Behavior, Animal / Q000502:physiology*; D018709:Statistics, Nonparametric
D002395:Catecholamines