Pharmacological studies of facial motoneurones in the rat.
Experiments were performed on 39 male albino rats anaesthetized with pentobarbitone sodium and paralyzed with gallamine triethiodide. Facial motoneurones consistently showed a progressive alteration of spike shape and decrease in spike firing frequency during the continuous microelectrophoretic application of the excitant amino acids D,L-homocysteate, L-glutamate, L-aspartate, and kainate, but infrequently during that of N-methyl-D-aspartate. The relative potencies of these excitants on facial motoneurones are reported. The potential usefulness of N-methyl-D-aspartate to produce amino acid-evoked motoneurone action potentials is discussed. The microelectrophoretically-applied depressant amino acid antagonist strychnine selectively and reversibly blocked the depressant effects of glycine on facial motoneurones. The depression of amino acid-induced firing of facial motoneurones by stimuli to the lingual or glossopharyngeal nerves were reversibly antagonized by microelectrophoretically applied strychnine but not by bicuculline.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D004347:Drug Interactions; D005145:Face / Q000294:innervation*; D005930:Glossopharyngeal Nerve / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology; D006710:Homocysteine / Q000494:pharmacology; D008036:Lingual Nerve / Q000187:drug effects / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D013331:Strychnine / Q000494:pharmacology
D005971:Glutamates; D011759:Pyrrolidines; D006710:Homocysteine; D001224:Aspartic Acid; D013331:Strychnine; D001640:Bicuculline