Differential discharge patterns of rhythmical activity in trigeminal motoneurons during fictive mastication and respiration in vitro.
Rhythmical activity in trigeminal motoneurons (TMNs) was studied in an in vitro neonatal rat brainstem preparation that retains functionally active circuits for oral-motor behaviors. Whole-cell current-clamp recording from TMNs demonstrated rhythmical activities during both spontaneously generated respiratory activity and neurochemically induced rhythmical oral-motor activity. TMNs showed spontaneous rhythmical (0.08 +/- 0.04 Hz) activities of burst-firing pattern during inspiration synchronized with inspiratory activities recorded in hypoglossal nerves. During rhythmical oral-motor activity induced by bath application of N-methyl-d,l-aspartic acid and the GABA(A) receptor antagonist bicuculline methiodide, TMNs showed only a rhythmical (5.6 +/- 0.8 Hz) pattern of single-spike discharge. TMNs never showed a burst-firing pattern during rhythmical oral-motor activity even when membrane potentials were shifted either to depolarized or hyperpolarized levels. Rhythmical activity in TMNs exhibited different discharge patterns between rhythmical oral-motor activity and respiratory activity generated in vitro.
Koizumi
Hidehiko
H
The First Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Osaka University, Suita, Osaka, Japan. koizumih@ninds.nih.gov
Ishihama
Kohji
K
Nomura
Kimiko
K
Yamanishi
Tadashi
T
Kogo
Mikihiko
M
Matsuya
Tokuzo
T
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D066298:In Vitro Techniques; D007568:Jaw / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement / Q000502:physiology; D018408:Patch-Clamp Techniques; D010507:Periodicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration; D014278:Trigeminal Nuclei / Q000166:cytology* / Q000502:physiology*