Stimuli associated with behavioral events may induce physiological responses which serve adaptive functions for both the individual and the species. One of the primary models for study of these behavior/endocrine interrelationships has been the study of the mechanisms whereby reproductive behavior induces the neural and endocrine changes necessary for initiation and maintenance of pregnancy or pseudopregnancy (PSP) in the female rat. In this species, genitosensory stimulation received during mating initiates twice-daily surges of prolactin (PRL) which prolong ovarian corpora luteal activity necessary for gestation. The behavioral patterns exhibited by the estrous rat during mating are the lordosis posture, solicitational behavior patterns which serve to indicate sexual readiness, as well as the patterning, or pacing, of contact with males which regulates the sequence and timing of copulatory stimulation received. Pacing behavior has been observed under naturalistic conditions and is exhibited spontaneously by estrous females in the laboratory when they are placed into experimental test chambers which allow them to control their contacts with sexually active male rats. This intermittent display of approach toward and withdrawal from contact with males relies exclusively for its expression on the ability of the female to discriminate between the intensity of the copulatory mounts received throughout the mating sequence; females display selective responses to mounts - without intromission, intromission, and ejaculation. The resulting pattern of cervical-vaginal stimulation received significantly increases the incidence of PSP or pregnancy above levels seen in females mated under test conditions in which they are not able to pace coital stimulation. Furthermore, paced mating stimulates rapid increases in plasma concentrations of LH and the 5alpha-reduced androgen, 3alphaandrostanediol, and contributes to the mating-induced release of PRL which occurs within 1 hr after mating. Thus, genitosensory stimulation received by the female during paced mating initiates several neuroendocrine responses which may directly contribute to induction of PSP. Despite the compelling evidence that paced mating has significant consequences for reproductive success in the rat, very little is known about the mechanisms whereby genitosensory stimulation is transduced into neuroendocrine responses. Experiments proposed in this application will examine the particular genitosensory stimuli received during paced mating which are important for initiation of PSP/pregnancy. They will examine which brain areas receive neural input around the time of mating and determine whether these areas are important for induction of PSP. In addition, studies will examine the effects of 3alpha-androstanediol on the display of pacing behavior. Finally, experiments will examine whether paced mating influences post-mating transport of sperm within the female's reproductive tract and the numbers of offspring produced.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD021802-11
Application #
2025142
Study Section
Special Emphasis Panel (ZRG2-BPO (01))
Project Start
1986-08-01
Project End
2001-03-31
Budget Start
1997-04-01
Budget End
1998-03-31
Support Year
11
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Boston University
Department
Type
Schools of Arts and Sciences
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Polston, E K; Heitz, M; Barnes, W et al. (2001) NMDA-mediated activation of the medial amygdala initiates a downstream neuroendocrine memory responsible for pseudopregnancy in the female rat. J Neurosci 21:4104-10
Polston, E K; Erskine, M S (2001) Excitotoxic lesions of the medial amygdala differentially disrupt prolactin secretory responses in cycling and mated female rats. J Neuroendocrinol 13:13-21
Lee, J W; Erskine, M S (2000) Changes in pain threshold and lumbar spinal cord immediate-early gene expression induced by paced and nonpaced mating in female rats. Brain Res 861:26-36
Lee, J W; Erskine, M S (2000) Pseudorabies virus tracing of neural pathways between the uterine cervix and CNS: effects of survival time, estrogen treatment, rhizotomy, and pelvic nerve transection. J Comp Neurol 418:484-503
Polston, E K; Centorino, K M; Erskine, M S (1998) Diurnal fluctuations in mating-induced oxytocinergic activity within the paraventricular and supraoptic nuclei do not influence prolactin secretion. Endocrinology 139:4849-59
Erskine, M S; Hanrahan, S B (1997) Effects of paced mating on c-fos gene expression in the female rat brain. J Neuroendocrinol 9:903-12
Frye, C A; Van Keuren, K R; Rao, P N et al. (1996) Analgesic effects of the neurosteroid 3 alpha-androstanediol. Brain Res 709:1-9
Frye, C A; McCormick, C M; Coopersmith, C et al. (1996) Effects of paced and non-paced mating stimulation on plasma progesterone, 3 alpha-diol and corticosterone. Psychoneuroendocrinology 21:431-9
Frye, C A; Van Keuren, K R; Erskine, M S (1996) Behavioral effects of 3 alpha-androstanediol. I: Modulation of sexual receptivity and promotion of GABA-stimulated chloride flux. Behav Brain Res 79:109-18
Lee, J W; Erskine, M S (1996) Vaginocervical stimulation suppresses the expression of c-fos induced by mating in thoracic, lumbar and sacral segments of the female rat. Neuroscience 74:237-49

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