NERVOUS SYSTEM REGULATION OF GENITAL REFLEXES

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DESCRIPTION: (Adapted from the Investigator's Abstract) The long term goals of this research are to understand the CNS regulation of female sexual reflexes. The present proposal will identify the inhibitory and excitatory pathways that control genital reflexes in the female. The majority of research on female sexual function has focused on the lordosis reflex. However, this does not address the genital responses related to sexual function. The urethrogenital [UG] reflex model is a spinal sexual reflex comprising of an integrated sympathetic, parasympathetic and somatic response in which sexually relevant genital reflexes can be studied in females. The responses seen with the UG reflex in the female rat mimic those present during sexual climax in humans. These studies are designed to examine the efferent neuronal pathways that control autonomic and somatic genital reflexes and to localize the spinal cord neurons that are activated during 'climactic' reflexes in the female. We hypothesize that male and female CNS control of genital reflexes are similar. A spinal pattern generator is thought to regulate genital reflexes but its location is unknown. We will use the activity sensitive marker, c-fos, to localize spinal neurons responsible for regulating genital reflexes. Genital reflexes are tonically inhibited by supraspinal neurons. We will identify the brainstem neurons responsible for mediating this inhibition and characterize the neurotransmitter involved. We hypothesize that serotonergic neurons in the nucleus paragigantocellularis [nPGi] inhibit the UG reflex. We will use a combination of neuroanatomical, physiological and pharmacological techniques to confirm this hypothesis and to elucidate the serotonergic receptors mediating the inhibition. We hypothesize that neurons in the medial preoptic area [MPOA] can initiate female genital reflexes. We will map the neurons and pathways that regulate the excitatory drive. The MPOA does not project directly to the spinal cord, therefore, excitatory pathways must relay in the brainstem. We will examine the hypothesis that MPOA descending pathways that drive genital reflexes relay in the periaqueductal gray. These studies will provide novel information on the organization, integration and control of CNS mechanisms involved in female sexual function. New information concerning the anatomical, functional and chemical specificity/heterogeneity of pathways modulating sexual reflexes in the female will be gained.