Summary
In decerebrate, paralyzed and artificially ventilated cats, we recorded the discharge of 64 motor axons supplying the pharyngeal muscles. Filaments containing motor axons, with discharges related to the respiratory cycle (phrenic nerve activity), were teased from the pharyngeal branches of the vagus and glossopharyngeal nerves. Most units (n = 41) fired only during expiration and exhibited a steady, a decreasing or a late augmenting discharge pattern. These units were found only in vagal filaments. Twenty three units discharged during inspiration and exhibited a steady, a late augmenting or a tonic discharge pattern. The inspiratory-related units were present in both the vagus (n=13) and glossopharyngeal (n=10) nerves. Nineteen of 20 pharyngeal inspiratoryrelated units tested were activated at short latency (range 3.4 to 8.0 ms) by stimulation of afferents in the superior laryngeal nerve (SLN). In 13 of these, such stimulation also suppressed their spontaneous activity. SLN stimulation elicited in all 17 pharyngeal expiratory-related units tested a short latency (range 0 to 8 ms) reduction of activity, followed in 7 units by an increase in activity. SLN stimulation occasionally evoked single or rhythmic multifibre bursts in the vagal pharyngeal filaments. These bursts, involving expiratory-related units, likely correspond to the buccopharyngeal stage of swallowing.
Similar content being viewed by others
References
Altschuler SM, Davies RO, Pack AI (1987) Role of medullary inspiratory neurones in the control of the diaphragm during oesophageal stimulation in cats. J Physiol (Lond) 391:289–298
Anch AM, Remmers JE, Sauerland EK, Degroot WJ (1981) Oropharyngeal patency during waking and sleep in the Pickwickian syndrome: electromyographic activity of the tensor veli palatini. Electromyogr Clin Neurophysiol 21:317–330
Bartlett D Jr (1986) Upper airway motor systems. In: NS Cherniack, JD Widdicombe (eds) Handbook of physiology, Section 3. The respiratory system, Vol. II. Control of breathing, Part 1. American Physiological Society, Bethesda, MD, pp 223–245
Basmajian JV, Dutta CR (1961a) Electromyography of pharyngeal constrictors and soft palate in rabbits. Anat Rec 139:443–449
Basmajian JV, Dutta CR (1961b) Electromyography of pharyngeal constrictors and levator palati in man. Anat Rec 139:561–563
Barillot JC, Bianchi AL, Gogan P (1984) Laryngeal respiratory motoneurones: morphology and electrophysiological evidence of separate sites for excitatory and inhibitory synaptic inputs. Neurosci Lett 47:107–112
Barillot JC, Bianchi AL, Grélot L, Pio J, Roman J (1987) Etude anatomique, morphologique et électrophysiologique des motoneurones des muscles du pharynx chez le chat. Arch Int Physiol Biochim 96:A000.
Bianchi AL (1971) Localisation et étude des neurones respiratoires bulbaires: mise en jeu antidromique par stimulation spinale ou vagale. J Physiol (Paris) 63:5–40
Bianchi AL, Grélot L, Iscoe S, Remmers JE (1988) Electrophysiological properties of rostral medullary respiratory neurones in the cat: an intracellular study. J Physiol (Lond) 407:293–310
Bonora M, Bartlett D Jr, Knuth L (1985) Changes in upper airway muscle activity related to head position in awake cats. Respir Physiol 60:181–192
Gautier H, Remmers JE, Bartlett D Jr (1973) Control of the duration of expiration. Respir Physiol 18:205–221
Guilleminault C, Hill MW, Simmons FB, Dement WC (1978) Obstructive sleep apnea: electromyographic and fiberoptic studies. Exp Neurol 62:48–67
Grélot L, Bianchi AL, Iscoe S, Remmers JE (1988) Expiratory neurones of the rostral medulla: anatomical and functional correlates. Neurosci Lett 89:140–145
Grélot L, Barillot JC, Bianchi AL (1989) Central distributions of the efferent and afferent components of the paryngeal branches of the vagus and glossopharyngeal nerves: a HRP study in the cat. Exp Brain Res 78: 327–335
Henneman E, Mendell LM (1981) Functional organization of motoneuron pool and its inputs. In: VB Brooks (ed). Handbook of physiology, Sec 1, Vol II, pp 1, Chap II. The nervous system. American Physiological Society, Washington, pp 423–507
Iscoe S (1988) Central control of the upper airway. In: OP Mathew, G Sant'Ambrogio (eds) Respiratory function of the upper airway. Marcel Dekker, New York, pp 125–192
Issa FG, Remmers JE (1989) Pathophysiology and treatment of obstructive sleep apnea. In: DH Simmon (ed) Current pulmonology. Year Book Medical Publishers, Inc, Chicago, 10:327–352
Jodkowski JS, Berger AJ (1988) Influences from laryngeal afferents on expiratory bulbospinal neurons and motoneurons. J Appl Physiol 64:1337–1345
Kawasaki M, Ogura JH, Takenouchi S (1964a) Neurophysiologic observations of normal deglutition. I. Its relationship to the respiratory cycle. Laryngoscope 74:1747–1765
Kawasaki M, Ogura JH, Takenouchi S (1964b) Neurophysiologic observations of normal deglutition. II. Its relationship to allied phenomena. Laryngoscope 74:1766–1780
Kirsten EB, St John WM (1978) A feline decerebration technique with low mortality and long term homeostasis. Pharmacol Meth 1:263–268
Miller AJ, Loizzi R (1974) Anatomical and functional differentiation of superior laryngeal nerve fibers affecting swallowing and respiration. Exp Neurol 42:369–387
Nail BS, Sterling GM, Widdicombe JG (1972) Patterns of spontaneous and reflexly-induced activity in phrenic and intercostal motoneurones. Exp Brain Res 15:318–322
Remmers JE, DeGroot WJ, Sauerland EK, Anch AM (1978) Pathogenesis of upper airway occlusion during sleep. J Appl Physiol 44:931–938
Remmers JE, Richter DW, Ballantyne D, Bainton CR, Klein JP (1986) Reflex prolongation of stage I of expiration. Pflügers Arch 407:190–198
Roman C (1986) Contrôle nerveux de la déglutition et de la motricité oesophagienne chez les mammifères. J Physiol (Paris) 81:118–131
Sauerland EK, Orr WC and Hairston LE (1981) EMG patterns of oropharyngeal muscles during respiration in wakefulness and sleep. Electromyogr Clin Neurophysiol 21:307–316
Sherrey JH, Megirian D (1975) Analysis of the respiratory role of pharyngeal constrictor motoneurons of cat. Exp Neurol 49:839–851
Sumi T (1963) The activity of brain stem respiratory neurons and spinal respiratory motoneurons during swallowing. J Neurophysiol 26:466–477
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Grélot, L., Barillot, J.C. & Bianchi, A.L. Pharyngeal motoneurones: respiratory-related activity and responses to laryngeal afferents in the decerebrate cat. Exp Brain Res 78, 336–344 (1989). https://doi.org/10.1007/BF00228905
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00228905