(STUDY OF PENELE ERECTION IN RATS DURING ELECTRICAL AND CHEMICAL STIMULATION OF THE HYPOTHALAMIC PARAVENTRECUALR NUCLEUS (PVN

Abstract

There has been a rapid advance in the understanding of the physiology of erection in the last few years as well as a great interest in evolving new treatment options for erectile dysfunction. Although present knowledge of spinal and brain mechanisms controlling penile erection is far from complete, many studies provide a better understanding of excitatory and inhibitory neural mechanisms involved in penile erection.

Specific brain areas, such as the hypothalamus, have been studied in relation to their role played in the process of penile erection. The paraventricular hypothalamic nucleus (PVN) and the medial preoptic area (MPOA) are brain nuclei that have attracted most interest since they have been identified as playing a major role in the initiation and maintenance of penile erection. For our studies, we decided to mainly focus on thePVN.

Many neurotransmitters, such as glutamate, dopamine and oxytocin, have been studied since these excitatory neurotransmitters cause penile erection when injected in the PVN. PVN neurons projects directly to the pudendal motor neurons and initiate penile erections.• In addition, the PVN projects to other brain stem regions involved in sexual function for example: periaqueductal grey, Barrington's nucleus, nucleus paragigantocellularis (nPGi) and the raphe pallidus and magnus. All these areas are known to project to the pelvic efferents and the nPGi has been shown to play an: "• . important role in controlling spinal sexual reflexes.