Phase-linked modulation of excitability of presynaptic terminals of low-threshold afferent fibers in the inferior alveolar nerve during cortically induced fictive mastication in the guinea pig.

Abstract

Excitability of presynaptic terminals of low-threshold primary afferent fibers in the inferior alveolar nerve was tested in the trigeminal spinal nucleus of the ketamine-anesthetized, paralyzed guinea pig, by Wall's method. Fictive mastication was induced by repetitive stimulation of the cortical masticatory area, and was monitored by rhythmical burst activity in the jaw-opening anterior digastric motoneuron pool. The excitability was rhythmically modulated in a phase-linked manner during the masticatory cycle: it was decreased coincidentally with the digastric burst activity (jaw-opening phase) and increased during the middle and late periods of the interburst phase (jaw-closing phase) of the masticatory cycle. The results imply that presynaptic modulation of synaptic transmission of peripheral inputs from primary afferents to interneurons in the jaw-opening reflex pathway may contribute to the rhythmical modulation of the jaw-opening reflex evoked by innocuous stimulation of the intraoral structures during mastication; presynaptic inhibition contributing to the depression of the jaw-opening reflex during the jaw-closing phase and presynaptic facilitation to its enhancement during the jaw-opening phase.

Cite this paper

@article{Kurasawa1988PhaselinkedMO, title={Phase-linked modulation of excitability of presynaptic terminals of low-threshold afferent fibers in the inferior alveolar nerve during cortically induced fictive mastication in the guinea pig.}, author={Ikuo Kurasawa and Yuki Hirose and Takeaki Sunada and Yuji Nakamura}, journal={Brain research}, year={1988}, volume={446 1}, pages={113-20} }