Cough, Expiration and Aspiration Reflexes following Kainic Acid Lesions to the Pontine Respiratory Group in Anesthetized Cats

I. POLIAČEK, J. JAKUŠ, A. STRÁNSKY, H. BARÁNI, E. HALAŠOVÁ¹,
Z. TOMORI²

Department of Biophysics, ¹Department of Biology, Comenius University, Jessenius Faculty of Medicine, Martin and ²Department of Pathophysiology, Faculty of Medicine, Šafárik University, Košice, Slovak Republic

Received March 31, 2003
Accepted May 16, 2003



Summary
The importance of neurons in the pontine respiratory group for the generation of cough, expiration, and aspiration reflexes was studied on non-decerebrate spontaneously breathing cats under pentobarbitone anesthesia. The dysfunction of neurons in the pontine respiratory group produced by bilateral microinjection of kainic acid (neurotoxin) regularly abolished the cough reflexes evoked by mechanical stimulation of both the tracheobronchial and the laryngopharyngeal mucous membranes and the expiration reflex mechanically induced from the glottis. The aspiration reflex elicited by similar stimulation of the nasopharyngeal region persisted in 73 % of tests, however, with a reduced intensity compared to the pre-lesion conditions. The pontine respiratory group seems to be an important source of the facilitatory inputs to the brainstem circuitries that mediate cough, expiration, and aspiration reflexes. Our results indicate the significant role of pons in the multilevel organization of brainstem networks in central integration of the aforementioned reflexes.


Key words
Pontine respiratoy group • Cough • Defensive airway reflexes • Kainic acid lesion • Cat