Adenosine, 'pertussis-sensitive' G-proteins, and K+ conductance in central mammalian neurones under energy deprivation.
There is a striking similarity between the effects of adenosine and of hypoxia or glucose depletion on membrane potential and conductance of hippocampal neurones in tissue slices of rat brain. Both induce a membrane hyperpolarization by an increase in potassium conductance. It seemed likely, therefore, that a rise in extracellular adenosine concentration during energy deprivation may link neuronal metabolism with membrane K+ conductance. To test this hypothesis, we have now investigated the effects of hypoxia/glucose deprivation on hippocampal neurones from pertussis toxin-treated rats. In such slices adenosine had no effect on postsynaptic membrane potential and input resistance. Nevertheless, hypoxia or glucose depletion were as effective as in controls. These data provide evidence against adenosine as the main mediator between cell metabolism and potassium conductance.
Spuler
A
A
Department of Physiology, University of Munich, F.R.G.
Grafe
P
P
D000241:Adenosine / Q000502:physiology*; D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D005947:Glucose / Q000502:physiology*; D006624:Hippocampus / Q000378:metabolism; D000860:Hypoxia; D066298:In Vitro Techniques; D008564:Membrane Potentials; D009474:Neurons / Q000378:metabolism; D037342:Pertussis Toxin; D015221:Potassium Channels / Q000378:metabolism*; D011199:Potentiometry; D051381:Rats; D010566:Virulence Factors, Bordetella
D015221:Potassium Channels; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D005947:Glucose; D000241:Adenosine