Axotomy of the vagal motor neurons by cervical vagotomy induces NADPH diaphorase staining due to increased nitric oxide synthase expression in both the rat dorsal motor nucleus and nucleus ambiguous; furthermore, cerical vagotomy leads to cell death of the dorsal motor nucleus cells. Subdiaphragmatic vagotomy axotomizes the vagal motor cells further from the brainstem than cervical vagotomy, and cuts the fibers running only to the abdominal viscera. Here we report that subdiaphragmatic vagotomy is sufficient to induce NADPH diaphorase staining in the dorsal motor nucleus but does not induce staining in the nucleus ambiguus. Because the neurons of the dorsal motor nucleus do not undergo cell death after subdiaphragmatic vagotomy and are able to re-enervate the gut, the increased nitric oxide synthase expression after distal axotomy may be related more to regeneration than degeneration.
Animal ; Fourth Ventricle/physiology* ; Fourth Ventricle/enzymology* ; Fourth Ventricle/cytology ; Male ; Motor Neurons/enzymology ; NADPH Dehydrogenase/metabolism* ; Rats ; Rats, Sprague-Dawley ; Vagotomy/methods* ; Vagus Nerve/physiology*

OBJECTIVETo determine the effect of the area postrema (AP) of the medulla oblongata on gastrointestinal interdigestive migrating motor complex (MMC) and the plasma motilin level.

METHODSInterdigestive MMC activities of the antrum and duodenum were recorded by strain gauge implanted on the serosa of 8 conscious dogs. A cannula was intubated in femoral vein for motilin injection. The plasma motilin concentration was measured by RIA. We observed: (1) normal interdigestive MMC activity and fluctuations in plasma motilin concentration; (2) the effects of electrically damaging the AP on MMC activity and plasma motilin level; (3) whether intravenous injection of motilin could induce phase III contractions after the AP was destroyed.

RESULTS(1) Typical interdigestive MMC with phase I, II, III, and IV was recorded in normal dogs. Phase III was concurrent with the peak of plasma motilin level. (2) In damaged AP dogs, antroduodenal interdigestive MMC contractions were suppressed; cyclic, phasic and migratory pattern of MMC was disrupted. Plasma motilin concentration was decreased. Intravenous injection of motilin could not induce phase III contractions.

CONCLUSIONSThe area postrema might play an important role, which is mediated by motilin, on the regulation of interdigestive MMC.

Animals ; Dogs ; Fourth Ventricle ; physiology ; Medulla Oblongata ; physiology ; Motilin ; blood ; Myoelectric Complex, Migrating ; physiology ; Stomach ; physiology

OBJECTIVE:To evaluate the normal figure of intracranial and intraspinal cerebrospinal fluid(CSF) dynamics, we report the results of the various parameters of cine phase contrast(PC) magnetic resonance(MR) CSF flow images throughout the whole neuraxis. METHODS: The MR images were obtained with 1.5T unit using the cine PC sequence with cardiac gating and gradient echo imaging in 10 normal persons(mean age, 30.4 years). The temporal velocity information from the anterior and posterior cervical pericord subarachnoid spaces, third and fourth ventricles, aqueduct, and lumbar cistern were plotted as wave forms. The wave forms were analyzed for configurations, amplitude parameters, and temporal parameters. The statistical significance of each parameter was examined with paired t-test. RESULTS: The actual flow of CSF were clearly visible with cine MR images. Throughout the whole neuraxis, the distinct reproducible configuration features were not obtained at ventricular or lumbar cistern, but at aqueduct and cervical pericord spaces. The temporal parameters were more important than the amplitude parameters. CONCLUSION: In this study, the authors demonstrated normal CSF dynamics and obtained further precision by plotting the temporal velocity information from the images as a waveform. This important basic information may be useful for understanding altered physiology in disease states such as syringomyelia and hydrocephalus.
Cerebrospinal Fluid* ; Fourth Ventricle ; Hydrocephalus ; Magnetic Resonance Imaging ; Physiology ; Subarachnoid Space ; Syringomyelia