Excitatory and inhibitory postsynaptic potentials in cat hypoglossal motoneurons during swallowing.
The postsynaptic potentials produced in cat genioglossus and styloglossus motoneurons (GG- and SG-Mns) during swallowing were studied. During swallowing elicited by placing water on the dorsum of the tongue, the GG-muscle discharged for 80-210 ms (mean +/- S. D. 123 +/- 31 ms, N = 59) and was abruptly suppressed, and the SG-muscle began discharging in synchrony with the GG-muscle and discharged for 200-360 ms (mean +/- S. D. 247 +/- 36 ms, N = 59). The GG- and the SG-Mns were identified if unitary muscle activity followed the induced spike of the motoneuron one-for-one. During swallowing, excitatory postsynaptic potentials (EPSPs) were evoked in the SG-Mns regardless of the respiratory drive on the SG-Mns, and inhibitory postsynaptic potential (IPSP) or EPSP-IPSP was evoked on the GG-Mns regardless of the respiratory drive on the GG-Mns. By increasing the intracellular concentration of chloride ions, the IPSP elicited in the GG-Mn during swallowing was turned into a depolarizing potential. In immobilized cats, a depolarizing potential and a depolarizing-hyperpolarizing potential sequence was evoked successively on a tongue retractor motoneuron and a tongue protruder motoneuron by repetitive electrical stimulation of the superior laryngeal nerve.
Tomomune
N
N
Department of Physiology, School of Dentistry, Tokushima University, Japan.
Takata
M
M
D000200:Action Potentials; D000818:Animals; D002415:Cats; D002712:Chlorides / Q000502:physiology; D003679:Deglutition; D004558:Electric Stimulation; D005260:Female; D007002:Hypoglossal Nerve / Q000502:physiology*; D007823:Laryngeal Nerves / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D014059:Tongue / Q000294:innervation* / Q000502:physiology
D002712:Chlorides