Serotonin inputs to laryngeal constrictor motoneurons in the rat.
OBJECTIVE
The objective was to demonstrate close appositions between serotonin-immunoreactive boutons and laryngeal constrictor (LCon) motoneurons in Sprague-Dawley rats.


METHODS
Animal experimental.


METHODS
LCon motoneurons were identified functionally by their antidromic responses to stimulation of the recurrent laryngeal nerve and postinspiratory modulation and were filled by intracellular injection of biotin amide (n = 6). The medulla was sectioned and, using immunohistochemical analysis, examined by light microscopy.


RESULTS
Serotonin appositions were found on all 6 LCon motoneurons, with an average number of 17 +/- 6 close appositions per neuron.


CONCLUSIONS
In comparison with the authors' previous study of inspiratory laryngeal motoneurons, the number of serotonin close appositions with LCon motoneurons was similar to that found with posterior cricoarytenoid motoneurons, but significantly less than that found with cricothyroid motoneurons. This finding may represent a basis for differences in tonic activity of laryngeal muscles observed in relation to the sleep-wake cycle.
Berkowitz
Robert G
RG
Hypertension and Stroke Research Laboratories, Department of Physiology, University of Sydney, Sydney, New South Wales, Australia.
Sun
Qi-Jian
QJ
Goodchild
Ann K
AK
Pilowsky
Paul M
PM
D000818:Animals; D004558:Electric Stimulation; D007150:Immunohistochemistry; D007821:Laryngeal Muscles / Q000294:innervation*; D008297:Male; D008564:Membrane Potentials; D009046:Motor Neurons / Q000737:chemistry* / Q000502:physiology; D017729:Presynaptic Terminals / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012009:Recurrent Laryngeal Nerve / Q000502:physiology; D012701:Serotonin / Q000032:analysis*
D012701:Serotonin