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Volga Neuroscience School 2016 Astroglial control of rhythm genesis in the brain
Role of Hypothalamic Glycine Receptors in Regulation of Male Sexual Behavior in Rats
N.A. Titova1*, Z.D. Zhuravleva1, M. Druzin1,3,1.V. Mukhina1,2
1 Neurotechnologies Department, Lobachevsky State University Of Nizhny Novgorod, Russia;
2 Department Normal Physiology named after N.Y. Belenkov, Central Scientific Research Laboratory, Nizhny Novgorod State Medical Academy, Russia;
3 Department of integrative Medical Biology, Umea University, Sweden. * Presenting e-mail: yanadya.titova@gmail.com
Medial preoptic area (MPOA) in the anterior hypothalamus is one of the main brain structures involved in regulation of sexual behavior in all vertebrate species. As it was previously shown, various manipulations with MPOA have a great impact on sexual performance, especially in males. Thus, electrical or/and pharmacological stimulation of the MPOA neuronal circuits facilitates sexual behavior in males, whereas lesions or pharmacological blockade of the neuronal activity in the MPOA dramatically impairs sexual performance. Although the details concerning the contribution of the MPOA to the appetitive and consummatory stages of sexual behavior are still under discussion, it is generally accepted that normal functioning of the MPOA is required for the integrity of the male sexual behavior.
The vast majority of studies concerning sexual behavior are performed on rats. The MPOA in rats contains several nuclei including the medial preoptic nucleus (MPN) also known as sexually dimorphic nucleus of the preoptic area. Both morphological and functional organization of the MPN significantly differs between the genders underlying gender-specific patterns of sexual and parental behavior in rats.
As the MPN has multiple reciprocal and unidirectional connections with many different brain structures such as accumbens, caudate putamen, ventral pallidum, amygdala and numerous nuclei in hypothalamus, thalamus and brain stem, the MPN neurons are thought to integrate sensory and endocrine information and to constitute the main part of central neuronal circuitry that controls most aspects of sexual behavior.
Most of the published research concerns the involvement of glutamatergic, GABAergic, serotonergic and dopaminergic neurotransmission in regulation of male sexual behavior. However, little is known about the role of glycinergic neurotransmission despite the fact that glycine receptors are widely expressed in the MPN. Glycine receptors are structurally and functionally very similar to the ionotropic GABAA receptors, together they mediate most of inhibition in the CNS as both of them are permeable for chloride, which entry into the neurons causes neuronal hyperpolarization
Our recent experimental data show an importance of glycine receptors in the MPN for the proper execution of sexual behavior in male rats as pharmacological manipulations of glycine receptor activity led to the changes in duration of copu-latory behavior and affected the time of the postejaculatory inhibition of sexual activity. Thus, our findings provide the very first experimental evidence for the involvement of glycine receptors in control of male sexual activity. However, further experiments are required to elucidate the precise mechanisms of glycine receptor-mediated regulation of sexual behavior.
Acknowledgments
The research was supported by Federal Target Program ''Research and development in priority areas of the development of the scientific and technological complex of Russia for 2014 - 2020" of the Ministry of Education and Science of Russia (Project ID RFMEFI58115X0016)
References
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OM&P
Opera Med Physiol 2016 Vol. 2 (S1) 81
