Experimentally induced postinhibitory rebound in rat nucleus ambiguus is dependent on hyperpolarization parameters and membrane potential.
Postinhibitory rebound (PIR), a transient depolarization subsequent to release from experimental hyperpolarization, was identified and characterized in 81% of the cells studied in the nucleus ambiguus in slices from medulla of rat. Hyperpolarizing current pulses were administered via the recording microelectrode in the bridge-balanced mode to test for PIR. The voltage trajectory was characterized by a depolarizing sag during the pulse, rebound depolarization (PIR) after the pulse and increased input resistance during rebound. The amplitude and time course of PIR were dependent on prepulse membrane potential, pulse amplitude and pulse duration. These results suggest a potential role of PIR in respiratory rhythmogenesis.
Department of Physiology, University of North Carolina, Chapel Hill 27599.
J B
JB
Dean
M
M
Czyzyk-Krzeska
D E
DE
Millhorn
D000818:Animals; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008564:Membrane Potentials; D009433:Neural Inhibition; D051381:Rats; D011919:Rats, Inbred Strains