NEURONS IN THE RAT-BRAIN AND SPINAL-CORD LABELED AFTER PSEUDORABIES VIRUS INJECTED INTO THE EXTERNAL URETHRAL SPHINCTER

Male Sprague-Dawley rats, with their pelvic and hypogastric nerves tra nsected, were infected with pseudorabies virus (PRV) injected into the external urethral sphincter. Animals were sacrificed at 2, 2.5, 3, an d 4 days postinfection. Spinal cord and brain tissue were sectioned an d processed by immunohistochemical techniques pith antisera against PR V and choline acetyl transferase (CAT). At 2 days postinfection, virus -labeled neurons were found in the ventrolateral divisions of Onuf's n ucleus and in the dorsal gray commissure (DGC). At progressively later incubation times, labeled neurons were found in the intermediolateral regions, the superficial layer of the dorsal horn, and the brainstem, in particular, the pontine micturition center. PRV/CAT-positive neuro ns were only found in Onuf's nucleus. Preganglionic neurons in the L6- S1 intermediolateral regions were CAT positive but PRV negative, thus suggesting that they are interneurons, not sacral parasympathetic preg anglionic neurons. After 4 days, virus had spread to neurons in the pa raventricular, preoptic, and even cortical regions. The distribution o f these PRV-labeled brain neurons strongly resembled that obtained aft er the injection of PRV into the urinary bladder (Nadelhaft et al. [19 92] Neurosci. Lett. 143:271-274). In both cases, neurons were labeled in the DGC in the spinal cord. The data therefore suggest that neurons in the DGC may be involved in the integrated control of the bladder a nd the external urethral sphincter. (C) 1996 Wiley-Liss, Inc.