Role of steroid hormones in the molecular biology of mu opioid receptor in different brain regions of female virgin rats cronically-treated with opioid agonist.

• Grant number: 10/17163-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2011
• End date: January 31, 2012
• Field of knowledge: Biological Sciences - Pharmacology - Neuropsychopharmacology
• Principal Investigator: Elizabeth Teodorov
• Grantee: Wesley Soares Cruz
• Host Institution: Centro de Matemática, Computação e Cognição (CMCC). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil

Abstract

In accordance with the principles of chronobiology, infradian rhythms that last longer than 24 hours are prevalent in mammals capable of breeding. The estrous cycle is well known in rodents, consisting of 4-5 days and characterized by the stages of proestrus, estrus, metaestrus and diestrus. The regulation of the secretion of pituitary gonadotrophins is the result of a complex interrelation between the effects of gonadal steroid feedback and influence on brain neurotransmitters in the hypothalamus-pituitary. Studies show that this phenomenon is played by brain opioids, which exert an inhibitory influence particularly in the secretion of gonadotrophins. It is known that different kinds of brain opioids (such as beta-enkephalins, enkephalins, dynorphins) exert their action by binding to specific membrane receptors, the best known being called mu, delta and kappa.Kappa and delta receptors appear to be associated with control of gonadotrophin secretion. On the other hand few studies demonstrate the real participation of mu receptors in this context. The experiments conducted so far reflect the binding potential of opioidergic agonists, like morphine, which could indicate modulation in the number of active opioid receptor type by the presence / absence of steroid hormones and physiological consequences. This study will use current techniques of molecular biology to assess the patterns of gene expression Oprm1 coding for mu opioid receptor as well as the MOR protein products in the hypothalamus, striatum and PAG of virgin rats and adult OVX and treated or not with morphine, Estrogen and Progesterone in accordance with the experiment.