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.