Potassium conductance increased by noradrenaline, opioids, somatostatin, and G-proteins: whole-cell recording from guinea pig submucous neurons.
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.
Tatsumi
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H
Vollum Institute, Oregon Health Sciences University, Portland 97201.
Costa
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Schimerlik
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North
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RA
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D003956:Dialysis; D004553:Electric Conductivity; D004745:Enkephalins / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006168:Guinea Pigs; D009294:Narcotics / Q000494:pharmacology*; D009474:Neurons / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology*; D037342:Pertussis Toxin; D011188:Potassium / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology; D017465:Receptors, Opioid, delta; D013004:Somatostatin / Q000494:pharmacology*; D013368:Submucous Plexus / Q000166:cytology / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D004745:Enkephalins; D009294:Narcotics; D011942:Receptors, Adrenergic, alpha; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D013004:Somatostatin; D006160:Guanosine Triphosphate; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D011188:Potassium; D009638:Norepinephrine