抄録
The intermediate gray layer (SGI) of the superior colliculus (SC) send descending motor command for orienting behaviors. SGI neurons receive cholinergic inputs from the midbrain cholinergic nuclei. In rats, we reported that cholinergic stimulation induced mostly fast inward + slow inward currents or fast inward + slow inward-outward currents in SGI neurons. Fast inward current is mediated by nicotinic receptors and both slow inward and slow outward currents by muscarinic receptors. We report the cholinergic responses of identified GABAergic SGI neurons in GAD67-GFP knock-in mice (17-24 days old) by whole-cell recordings in SC slices. Current responses to 30 μM carbachol were investigated in the presence of TTX. The most common response pattern was fast inward current alone (26/54), found mainly in fast spiking GABAergic neurons (25/29). The second common pattern was fast inward + slow inward current (21/54), found in burst spiking (18/22), late spiking (2/2) and fast spiking (1/29) GABAergic neurons. These results suggest that the cholinergic inputs may exert facilitatory effects on SGI GABAergic neurons in the mouse SC. [Jpn J Physiol 55 Suppl:S149 (2005)]
