Effects of site-specific CNS microinjection of cholecystokinin on lordosis behavior in the male rat.
We have previously demonstrated that intracerebroventricular injections of sulphated cholecystokinin octapeptide (sCCK-8) had a dramatic facilitatory effect on lordosis behavior in the gonadectomized, estrogen-primed male rat. In the female, sCCK-8 facilitates or inhibits lordosis when microinjected into the medial preoptic nucleus (MPN) or ventromedial nucleus of the hypothalamus (VMH), respectively. In order to identify sCCK-8 responsive sites that modulate lordosis behavior in gonadectomized males, sCCK-8 was microinjected into the MPN or VMH. Sulphated CCK-8 significantly increased lordosis behavior when microinjected into the MPN of estrogen-primed males, but had no significant effects when microinjected into the VMH. These results imply that CCK-sensitive neural substrates within the MPN may act to disinhibit lordosis in the gonadectomized, estrogen-primed male rat. The lack of an effect of VMH injection of sCCK-8 on lordosis in males is discussed in terms of possible sex differences in sCCK-8-sensitive lordosis-modulating circuits.
Bloch
G J
GJ
Department of Anatomy, UCLA School of Medicine 90024.
Dornan
W A
WA
Babcock
A M
AM
Gorski
R A
RA
Micevych
P E
PE
D000818:Animals; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology; D008297:Male; D011301:Preoptic Area / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011949:Receptors, Cholecystokinin / Q000187:drug effects*; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D012844:Sincalide / Q000494:pharmacology*; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects*
D011949:Receptors, Cholecystokinin; D004958:Estradiol; D012844:Sincalide