William P. Norman

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Our purpose was to determine the central vagal sites for regulating changes in lower esophageal sphincter (LES) pressure in the cat. Injection of the retrograde tracer, horseradish peroxidase, into the LES resulted in labeling of cells in the dorsal motor nucleus of the vagus (DMV), with the largest number of cells appearing in two areas, one area rostral(More)
We previously demonstrated that GABA and muscimol administered either into the cisterna magna or the fourth ventricle to chloralose-anesthetized cats cause respiratory depression, hypotension, and bradycardia. Injection of these substances into the lateral and third ventricles had no effect. In order to localize the site of action, muscimol and GABA were(More)
Thyrotropin-releasing hormone (TRH) is clearly implicated in the control of gastric function via interactions in the dorsal motor nucleus of the vagus (DMV) of the cat. The source of the TRH innervation of the DMV is important to determine because this region could be of importance in control of gastric function. TRH-immunoreactive (ir) neurons are located(More)
The purpose of the present study was to determine whether blockade of excitatory amino acid receptors at the ventrolateral nucleus of the tractus solitarius would influence respiratory activity. This was done by microinjecting excitatory amino acid receptor antagonists into the ventrolateral nucleus of the tractus solitarius of alpha-chloralose-anesthetized(More)
Retrograde tracing with a fluorescent dye (Fast Blue) combined with immunohistochemistry was used to identify putative neurotransmitter(s) at the phrenic motor nucleus in the cat. Fast Blue was injected bilaterally into the diaphragm of five cats, where each phrenic nerve enters the muscle. Seven days later the animals were perfusion fixed and tissue(More)
We investigated the effects of stimulation of the nucleus ambiguus (NA) complex on gastroduodenal motility and gastric secretion in alpha-chloralose-anesthetized cats. Motility was measured by use of extraluminal force transducers sutured to the body, antrum, pylorus, and duodenum. Secretion was measured by determining changes in gastric pH, titratable(More)
Previous studies indicate that the new antihypertensive drug, urapidil, acts at the ventral surface of the medulla in cats to produce a fall in blood pressure. In addition, urapidil was found in receptor binding studies to have a relatively high affinity for the serotonin 1A receptor. These results suggest that drugs which bind to the serotonin 1A receptor(More)
Blockade of gamma-aminobutyric acid receptor function by direct microinjection of bicuculline into the nucleus ambiguous in cats produced a marked increase in gastric motility which was mediated by the vagus nerve. This effect was reversed by muscimol. These data indicate that the nucleus ambiguous may be an important brain site influencing gastric function(More)
In this study, the distribution of neurons containing the adrenaline-synthesizing enzyme phenylethanolamine-N-methyltransferase (PNMT) was mapped in the medulla of the cat. Data from recent studies in the rat suggest that the anatomical structure responsible for cardiorespiratory changes that occur following application of neurotransmitters and drugs to(More)