INPUT AND OUTPUT NEURONAL STRUCTURES OF THE PONTINE MICTURITION CENTER

Part II. Mainly Output Neuronal Structures

Abstract

In this study, Axonal trajectories and terminal fields of efferent fibers originating from cells in the pontine micturition center (PMC) were studied. To do this, wheat germ agglutinin-horseradish peroxidase (WGA-HRP) or phaseolus vulgaris leucoagglutinin (PHA-L) were injected into the PMC.
WAG-HRP and PHA-L were microinjected into the nucleus locus coeruleus alpha. The pathways of labeled fibers almost corresponded to the rostral and caudal limbs of the dorsal periventricular pathway, the noradrenergic fibers passing to the cerebellum, the caudal limb of the dorsal noradrenergic bundle and coeruleospinal pathway which were known as efferent pathways of the locus coeruleus complex. Most labeled terminals and presumed terminals were identified in the sites where WGA-HRP labeled cells were located between the cerebral cortex and the sacral spinal cord. Many of labeled terminals and presumed terminals existed in the periaqueductal gray, nucleus reticularis pontis oralis, nucleus reticularis magnocellularis and sacral intermediate gray where the nucleus of origin of the pelvic nerve was located. Some of them were located in the ventrolateral and lateral pontine tegmental fields which were called the pontine urine-strage nucleus, lumber intermediate gray where the nucleus of origin of the hypogastric nerve was located, and the Onuf's nucleus which was the nucleus of origin of the pudendal nerve.
These results clearly demonstrated that a number of efferent projection sites from the PMC correspond to afferent projection sites within the brain and the spinal cord to the PMC.