Cough and Laryngeal Muscle
Discharges in Brainstem Lesioned Anesthetized Cats
I. POLIAČEK, A. STRÁNSKY, M.
SZEREDA-PRZESTASZEWSKA2, J. JAKUŠ, H. BARÁNI, Z.
TOMORI3, E. HALAŠOVÁ1
Department of Medical Biophysics, 1Department of
Biology, Jessenius Faculty of Medicine, Comenius University,
Martin, Slovak Republic, 2Laboratory of Respiration
Physiology, Polish Academy of Sciences, Medical Research Center,
Poland and 3Department of Pathophysiology, Faculty of
Medicine, Šafárik University, Košice, Slovak Republic
Received March 11, 2004
Accepted December 15, 2004
On-line available February 16, 2005
Summary
Experiments were carried out to determine whether there are
separate drives from the selected neuronal networks of the
brainstem affecting the discharge patterns of laryngeal and
respiratory pump muscles during cough. Twenty-four
non-decerebrate spontaneously breathing cats anesthetized with
sodium pentobarbitone were used. Microinjections of kainic acid
into the lateral tegmental field of the medulla, medullary
midline or pontine respiratory group eliminated the cough evoked
by mechanical stimulation of the tracheobronchial and
laryngopharyngeal mucosa. These stimuli, in most cases, provoked
irregular bursts of discharges in the posterior cricoarytenoid
and thyroarytenoid laryngeal muscles (or they had no effect on
them). No pattern of laryngeal muscle activities following
lesions resembled the laryngeal cough response. Lesions of the
target regions did not result in any apparent changes in the
eupnoeic pattern of laryngeal activity. Neurons of the medullary
lateral tegmental field, raphe nuclei and the pontine
respiratory group seem to be indispensable for the configuration
of the central cough motor pattern. However, these neurons do
not appear to be essential for the discharge patterns of
laryngeal motoneurons during eupnoea. The residual laryngeal
„cough“ responses are probably mediated by an additional motor
drive.
Key words
Cough • Laryngeal abductor • Laryngeal adductor • Kainic acid
brainstem lesion • Cat
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