Effect on breathing of neuronal dysfunction in the caudal ventral
medulla of goats.
Ohtake, P. J., H. V. Forster, L. G. Pan, T. F. Lowry, M. J. Korducki,
K. Smith, and A. L. Forster.
Department of Physiology, Medical College of Wisconsin, Zablocki
Veterans Administration Medical Center and Program in Physical
Therapy, Marquette University, Milwaukee, WI 53226
APStracts 2:0278A, 1995.
It has been reported that the caudal ventrolateral medulla (VLM) is
important in central chemoreception and the control of breathing. The
objective of this study was to determine in adult goats the effects
on breathing of neuronal dysfunction of this caudal VLM region (area
L; caudal to rostral hypoglossal nerve rootlet). Thermodes were
chronically implanted on the VLM to cool neurons and thereby cause
neuronal dysfunction. During awake and (halothane) anesthetized
states, cooling the caudal VLM for 20 seconds to 20 degrees C did not
alter breathing (P>.10). However, between 20 and 30 seconds of
cooling and during recovering from cooling 0-4 mm caudal to the
rostral hypoglossal rootlet, there was a 12 (awake) to 25%
(anesthetized) increase (P<.05) in breathing. This tachypneic
hyperpnea was uniform over conditions of eucapnia, hypercapnia and
hypoxia and resulted from reduced inspiratory time which increased
frequency. We conclude that in goats inhibitory neurons are located
in area L and the lateral caudal ventral medulla.
Received 12 October 1994; accepted in final form 20 June 1995.
APS Manuscript Number A1068-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.