Central inspiration increases barosensitivity of neurons in rat rostral ventrolateral medulla
Date
1995
Authors
Miyawaki, T.
Pilowsky, P.
Sun, Q.J.
Minson, J.
Suzuki, S.
Arnolda, L.
Llewellyn-Smith, I.
Chalmers, J.
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Journal article
Citation
American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 1995; 268(4):R909-R918
Statement of Responsibility
Takashi Miyawaki, Paul Pilowsky, Qi-Jian Sun, Jane Minson, Satoshi Suzuki, Leonard Arnolda, Ida Llewellyn-Smith, and John Chalmers
Conference Name
Abstract
Barosensitive neurons in the rostral ventrolateral medulla (RVLM) often have a respiratory-related modulation of their activity. However, the extent of the interaction between baroreceptor and respiratory inputs is controversial. The main aim of the present study was to determine the effect of central respiratory drive (CRD) on the barosensitivity of RVLM neurons. Extracellular recordings were obtained from 68 barosensitive neurons in the RVLM of anesthetized, paralyzed, and bilaterally vagotomized Sprague-Dawley rats. Examination of phrenic-triggered histograms revealed five activity patterns among barosensitive neurons: inspiratory depression (type I, n = 20), early inspiratory activation (type II, n = 14), postinspiratory activation (type III, n = 18), expiratory depression (type IV, n = 5) and no modulation (type V, n = 11). In most neurons (types I and III and 56% of type II) inhibition produced by aortic nerve stimulation was greater in inspiration than in expiration. Cardiac-related modulation, as an index of natural phasic baroreceptor activation, was also greater in inspiration than expiration in type III neurons. The results demonstrate that CRD modulates the baroreflex at the level of the RVLM.
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Copyright © 1995 the American Physiological Society