The purpose of the proposed research is to establish that cytoarchitectonically discrete, sexually dimorphic cell groups of the medial preoptic area (MPOA) are regulated by gonadal steroids in adulthood to affect reproductive function. Recent research indicates that the MPOA of the rat is composed of numerous distinct components. some of which are sexually dimorphic and which respond to gonadal steroids in adulthood with changes in morphology. Based on the assumption that a continued, detailed study of components of this relatively large brain region is essential in order to elucidate its functions, the specific aims of the proposed research are to establish that: 1) Steroid regulation of the neuropeptide galanin (GAL) takes place within sexually dimorphic cell groups of the MPOA, and 2) The activity of GAL and cholecystokinin octapeptide (CCK-8) within the medial preoptic nucleus (MPN) contributes to the regulation of reproductive behaviors and sex differences in their expression.
Specific Aim I : Based on preliminary evidence, immunohistochemical methods can be used to identify GAL-immunoreactive(-I) cells within the MPOA, and this technique can be used to establish that GAL-I cells are localized within sexually dimorphic subcomponents, that gonadal steroids maintain levels of GAL activity within these cell groups, that gonadal steroid-concentrating cells can also be GAL-immunoreactive, and that there are sex differences in the distribution of GAL-I cells.
Specific Aim II : Preliminary evidence indicates that unilateral microinjection of GAL into the MPN can decrease intromission latency (IL) in testosterone-treated gonadectomized males, and that MPN microinjection of sulphated CCK-8 (sCCK-8) has a dramatic facilitatory effect on lordosis behavior in estrogen-treated gonadectomized females and males. These findings are the basis for a series of experiments that will elucidate the role played by GAL in affecting male copulatory behavior and lordosis behavior in males and females, and the role played by testosterone and its metabolites in regulating the GAL- and sCCK-8-induced changes in these behaviors. In addition to the strong likelihood that this research will define a functional system within a discrete portion of the MPOA, the results may add significantly to our understanding of neural mechanisms responsible for sex differences in the expression of reproductive behaviors in adulthood.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD027334-04
Application #
2200380
Study Section
Biopsychology Study Section (BPO)
Project Start
1991-08-01
Project End
1996-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
4
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Brigham Young University
Department
Psychology
Type
Other Domestic Higher Education
DUNS #
City
Provo
State
UT
Country
United States
Zip Code
84602
Butler, P C; Mills, R H; Bloch, G J (2001) Inhibition of lordosis behavior in male and female rats by androgens and progesterone. Horm Behav 40:384-95
Lephart, E D; Butler, P C; Mills, R H et al. (1998) Effects of testosterone and progesterone on brain 5alpha-reductase and aromatase in Long-Evans males and comparison of aromatase in Long-Evans vs. Sprague-Dawley rats. Brain Res 789:327-30
Bloch, G J; Butler, P C; Eckersell, C B et al. (1998) Gonadal steroid-dependent GAL-IR cells within the medial preoptic nucleus (MPN) and the stimulatory effects of GAL within the MPN on sexual behaviors. Ann N Y Acad Sci 863:188-205
Kohlert, J G; Bloch, G J (1996) Hyperactivity in hyposexual male rats. Physiol Behav 59:171-8
Bloch, G J; Butler, P C; Kohlert, J G (1996) Galanin microinjected into the medial preoptic nucleus facilitates female- and male-typical sexual behaviors in the female rat. Physiol Behav 59:1147-54
Bloch, G J; Mills, R (1995) Prepubertal testosterone treatment of neonatally gonadectomized male rats: defeminization and masculinization of behavioral and endocrine function in adulthood. Neurosci Biobehav Rev 19:187-200
Bloch, G J; Mills, R; Gale, S (1995) Prepubertal testosterone treatment of female rats: defeminization of behavioral and endocrine function in adulthood. Neurosci Biobehav Rev 19:177-86
Bloch, G J; Kurth, S M; Akesson, T R et al. (1992) Estrogen-concentrating cells within cell groups of the medial preoptic area: sex differences and co-localization with galanin-immunoreactive cells. Brain Res 595:301-8