Further promiscuity of phenylalkylamine Ca antagonists

The June issue of TiPS included an .article by Dragunow and Faull on the possible role of adenosine in preventing cell death follow- ing seizures, hypoxia and hypo- glycaemia ~. It is well known that one of the effects of hypoxia is to reduce spontaneous and evoked synaptic activity both in vivo 2"3 and in vitro 4,s. We have recently shown that in the isolated spinal cord hypoxia-induced synaptic depres- sion is prevented by the adenosine antagonist 8-cyclopentyltheophyl- line (10-6M) providing strong support for the hypothesis that the underlying neurochemical mech- anism mediating the synaptic depression is adenosine 6. These 'silenced' neurons are viable as evidenced by functional recovery subsequent to the hypoxic period °. Since functional inactivity reduces energy expenditure, this is likely to contribute to prolongation of cell viability.