Substance P inputs to laryngeal motoneurons in the rat.
Substance P terminals have previously been demonstrated around retrogradely labelled posterior cricoarytenoid (PCA) motoneurons, but little is known regarding substance P inputs to other functionally identified laryngeal motoneurons. In the present study, we determined the number and distribution of close appositions between substance P immunoreactive boutons and three types of laryngeal motoneuron by using a combination of intracellular recording, dye-filling and immunocytochemistry in the rat. Cricothyroid (CT) motoneurons received 15+/-5 substance P appositions/neuron (mean+/-S.D., n = 6), PCA motoneurons received 13+/-5 (n = 6), and laryngeal constrictor (LCS) motoneurons received 11+/-4 (n = 5). In contrast to our previous finding of a preferential serotonin innervation of CT motoneurons, we found no significant difference between the substance P inputs to CT, PCA and LCS motoneurons. Our results indicate a modest role for substance P in control of laryngeal motoneuronal function.
Sun
Qi-Jian
QJ
Hypertension and Stroke Research Laboratories, Department of Physiology, University of Sydney, Sydney, NSW 2006, Australia.
Berkowitz
Robert G
RG
Goodchild
Ann K
AK
Pilowsky
Paul M
PM
D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D007150:Immunohistochemistry; D007821:Laryngeal Muscles / Q000294:innervation; D007823:Laryngeal Nerves / Q000378:metabolism / Q000648:ultrastructure*; D008297:Male; D008564:Membrane Potentials; D009046:Motor Neurons / Q000378:metabolism / Q000648:ultrastructure*; D009434:Neural Pathways; D010791:Phrenic Nerve / Q000502:physiology; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013373:Substance P / Q000378:metabolism*
D013373:Substance P