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Motor cortical control of cardiovascular bulbar neurones projecting to spinal autonomic areas
Author(s) -
Viltart Odile,
Mullier Olivia,
Bernet François,
Poulain Pierre,
BaM'Hamed Saadia,
Sequeira Henrique
Publication year - 2003
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.10598
Subject(s) - rostral ventrolateral medulla , medulla , brainstem , motor cortex , medulla oblongata , stimulation , neuroscience , cortex (anatomy) , catecholamine , medicine , central nervous system , anatomy , endocrinology , biology
There is evidence that the motor cortex is involved in cardiovascular adjustments associated with somatic motor activity, as it has functional connections with the ventrolateral medulla, a brainstem region critically involved in the control of blood pressure and the regulation of plasma catecholamine levels. The ventrolateral medulla sends projections to the spinal intermediolateral nucleus, where preganglionic neurones controlling heart and blood vessels (T2 segment) and adrenal medulla (T8 segment) are found. The aim of the present study was to determine whether electrical stimulation of the rat motor cortex induces cardiovascular responses and Fos expression in ventrolateral medulla neurones projecting to the T2 and T8 segments. After a set of experiments designed to record cardiovascular parameters (blood pressure and plasma catecholamine levels), injections of retrograde tracer (Fluorogold) were performed in the intermediolateral nucleus of two groups of rats, at the T2 or at the T8 segmental levels. Five days later, the motor cortex was stimulated in order to induce Fos expression in the ventrolateral medulla. Stimulation of the motor cortex induced: (1) hypotension and a significant decrease in plasma noradrenaline levels, and (2) a significant increase in the number of the double‐labelled neurones in the rostral ventrolateral medulla projecting to T2. These data demonstrate that cardiovascular adjustments, preparatory to, or concomitant with, motor activity may be initiated in the motor cortex and transmitted to cardiac and vasomotor spinal preganglionic neurones, via the ventrolateral medulla. © 2003 Wiley‐Liss, Inc.