IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Muscarinic modulation of gamma band activity in the pedunculopontine nucleus (PPN)
Autor/es:
N. KEZUNOVIC; J. HYDE; B. GOITIA; V. BISAGNO; F. J. URBANO; E. GARCIA-RILL
Lugar:
San Diego
Reunión:
Congreso; Neuroscience 2013; 2013
Institución organizadora:
Society for Neuroscience
Resumen:
The pedunculopontine nucleus (PPN) is part of the reticular activating system, and receives cholinergic input from the contralateral PPN and laterodorsal tegmental nuclei. We reported that persistent application of the nonspecific cholinergic agonist carbachol (CAR) increased the frequency of oscillatory activity in PPN neurons, which we identified as dependent on voltage-gated, high threshold P/Q-type calcium channels. Here, we tested the hypothesis that M2 muscarinic receptors and G-proteins associated with M2 receptors mediate the increase in CAR-induced oscillatory frequency in PPN cells. Whole-cell patch-clamp responses were recorded on 9-13 day old rat brainstem slices at 370C perfused with oxygenated aCSF in an immersion chamber containing the synaptic blockers gabazine (GABAA antagonist), strychnine (glycine antagonist), 6-cyano-7-nitroquinoxaline-2,3-dione (AMPA/kainate receptor antagonist), APV (NMDA receptor antagonist), and mecamylamine (nicotinic receptor blocker), and also Tetrodotoxin to block sodium channels. Using 30 sec depolarizing ramps, PPN neurons (n=185) began oscillating around -40 mV and reached their peak around -20 mV membrane potential. Acute (short duration) application of CAR blocked the oscillatory activity through M2 muscarinic receptors (blocked by the M2 antagonist pirenzepine, but not the M1 antagonist methoctramine), an effect reversed with atropine. However, persistent (long duration) application of CAR significantly increased the frequency of ramp-induced oscillatory activity in PPN neurons through M2 receptors [40±1Hz (CAR) vs 23±1Hz (without CAR); p