Amygdaloid-induced jaw opening and facilitation or inhibition of the trigeminal motoneurons in the rat.
1. Repetitive stimulation of the rat'se central amygdaloid (CAm) nucleus induced rhythmic masticatory jaw movements or continuous jaw opening. Both types of jaw movements were accompanied by coincidental activities of the mylohyoid (Myl) nerve. 2. The effects of CAm stimulation were examined on activities of bilateral Myl and masseteric (Mass) nerves or their motoneurons (Myl-Dig and Mass, respectively). 3. CAm stimulation induced contralaterally dominant facilitation of the Myl nerve activity as well as Myl-Dig motoneurons. These facilitatory effects were caused by EPSPs seen in Myl-Dig motoneurons. 4. One third of the Mass motoneurons were inhibited or hyperpolarized by contralateral CAm stimulation, while a few were facilitated and the majority unaffected.
D000200:Action Potentials; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D008409:Mastication; D008410:Masticatory Muscles / Q000294:innervation* / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D014278:Trigeminal Nuclei / Q000502:physiology*