Reproductive success in the male rat depends on the ability to recognize appropriate sexual cues, motivation to respond to those cues, and coordination of the necessary motor sequences required to optimize sexual performance and an ejaculatory response. Early maternal environment is important in the normal development of copulatory behavior. Manipulation of this early social stimulation results in alterations in male sexual behavior and in the functioning of mediating endocrine and neurotransmitter systems.
The present series of studies were designed to explore the effects of early life maternal deprivation and replacement maternal licking-like stimulation on the development of male rat sexual behavior and the neurophysiological mechanisms which mediate sexual performance with specific attention to the dopamine (DA) and androgen systems.
Long-Evans male rats were reared with or without their mothers through the use of the artificial rearing (AR) paradigm. Half of the AR rats were provided with licking-like stimulation, consisting of periodic stroking with a paintbrush. In study 1, AR and maternally-reared (MR) rats were tested in adulthood for sexual behavior. Neuronal activation in response to copulation was assessed using an antibody against the protein product of the immediate early gene c-fos in brain regions that sub-serve sexual behavior. Study 2 explored whether sexual behavioral deficits observed in AR males can be reversed by later sexual experience. In this study, animals were sacrificed following a ninth copulatory trial and Fos immunoreactivity, androgen and estrogen-α receptors were assessed. In study 3, the effects of early maternal deprivation on partner preference in both males that are differentially reared, and, female preference towards these males were investigated. This explored if any behavioral deficits observed in AR males could be attributed to differences in their attractivity to females. Study 4 investigated the effects of early maternal deprivation on androgen sensitivity in adult males. Copulatory response to a receptive female was examined post-castration in AR and MR males and again following testosterone replacement. In study 5, levels of extracellular DA were investigated in the nucleus accumbens, an area critical in motivation, prior to and during copulation in sexually experienced AR and MR males using Microdialysis.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/19169 |
| Date | 01 March 2010 |
| Creators | Akbari, Emis |
| Contributors | Fleming, Alison S. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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