Responses of respiratory-modulated facial nerve activity to activation of the ventrolateral subarea of the nucleus of the tractus solitarius.
The purpose of the present study was to examine respiratory-modulated facial nerve activity (FNA) in response to activation of the ventrolateral subarea of the nucleus of the tractus solitarius (vlNTS). The cat was anesthetized with sodium pentobarbital and then vagotomized bilaterally, paralyzed and ventilated artificially. End-tidal fractional concentration of CO2 was maintained at hyperoxic normocapnia. Partial occipital craniotomy was performed to expose the obex. Activities of the phrenic and the facial nerves were simultaneously recorded. The vlNTS was excited by electrical current (80 Hz frequency, 0.5 ms pulse duration and a variety of current from 12.5 to 50 microA) and glutamate (30-100 nl, 0.5 M). Three responsive patterns for both nerves were observed in response to vlNTS activation. First, inspiratory facial nerve activity (iFNA) and phrenic nerve activity (PNA) were decreased (p < 0.01), while expiratory facial nerve activity (eFNA) was not changed. Second, iFNA and PNA were diminished (p < 0.01) but eFNA was enhanced. Third, iFNA was decreased whereas PNA was enhanced. These results suggest that there might be a neural pathway projecting from the vlNTS to the facial nuclei to modulate respiratory-modulated facial nerve activities.
Lin
C Y
CY
Institute of Physiology, National Yang-Ming University, Tapiei, Taiwan, R.O.C.
Hwang
J C
JC
D000818:Animals; D001794:Blood Pressure; D002415:Cats; D004558:Electric Stimulation; D005154:Facial Nerve / Q000502:physiology*; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology; D008297:Male; D009431:Neural Conduction; D009434:Neural Pathways / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology*; D012119:Respiration / Q000502:physiology*; D017552:Solitary Nucleus / Q000502:physiology*
D018698:Glutamic Acid