Journal of Neuroscience, Vol 10, 1675-1682, Copyright © 1990 by Society for Neuroscience
Potassium conductance increased by noradrenaline, opioids, somatostatin, and G-proteins: whole-cell recording from guinea pig submucous neurons
H Tatsumi, M Costa, M Schimerlik and RA North
Vollum Institute, Oregon Health Sciences University, Portland 97201.
Agonists at alpha 2-adrenoceptors, delta-opioid receptors, and somatostatin
receptors were applied to dissociated guinea pig submucous plexus neurons;
whole-cell recordings of membrane current showed that they increased the
membrane potassium conductance. The conductance affected showed inward
rectification, being described by Gag(max)/[1 + exp((V - V0.5)/k)] where
V0.5 was about -65 mV and Gag(max) was about 10 nS. The agonists were
ineffective when the potassium conductance of the neurons had first been
increased by intracellular dialysis with purified guanosine 5'-triphosphate
(GTP)-binding proteins (Gi or Go). Agonist actions were prevented by
pertussis toxin, applied intracellularly (10-100 ng/ml for several minutes)
or extracellularly 1- 10 micrograms/ml for 1 hr); in the latter case, the
agonist responses were reconstituted by intracellular dialysis with
GTP-binding proteins.
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