The storage and periodic release of urine is controlled from several levels of the central nervous system (CNS) including the lumbosacral spinal cord, rostral pons, hypothalamus, subcotical nuclei, and the cerebral cortex. Various evidence indicates that the excitatory parasympathetic component of the mictudtion reflex is dependent upon supraspinal pathway originating in the rostral pons (""""""""pontine micturition center"""""""" - PMC) and sending descending fibers to the sacral spinal cord. The studies outlined in the present proposal are designed to provide a detail analysis, using modem neuroanatomical, neurophar macological and neurophysisological techniques, of pontine and suprapontine structures which modulate the micturition reflex pathway.
The aims of this proposed research are: 1) To determine, using electrical stimulation, sites within the cortex, hypothalamus, and areas adjacent to hypothalamus which modulate bladder reflexes. 2) To examine the effects of L-glutamate microinjected into those sites which give positive results (either inhibition or facilitation) with electrical stimulation. (L-glutamate witl be used here as pharmacological tool to determine whether cell bodies or axons-in-passage are being activated by the electrical stimulation - L-glutamate being active only at cell bodies.) 3) To study in detail the modulation by hypothalamic and cortical sites on: a) isometric rhythmic bladder contractions, b) voiding cystometrogram (CMG), c) sympathetic input to bladder via the hypogastric nerve, d) electromyogram (EMG) of the external urethral sphincter, e) reflex evoked activity to pelvic nerve stimulation and f) single and multiunit activity at the level of the PMC and pelvic nerve efferents. 4) To determine using immunohistochemical techniques the possible neurotransmitters which mediate modulation by these suprapontine sites, and to follow these studies with neuropharmacological studies to determine the effects of agonist and especially antagonist of these putative neurotransmitters mediating the modulatory effects. 5) To determine the location of neurons in pontine and suprapontine structures (especially cortical and hypothalamic sites) which express the oncogene C-los to electrical stimulation of bladder afferents. The information gained in this study will not only provide a much more complete wiring diagram for the micturition pathway but may also suggest possible pharmacological modification of the act of micturition.
