We investigated the effects of
2R,4R-APDC, a selective group II
metabotropic glutamate receptor (II mGluR) agonist, on certain behaviors in rats subjected and non-subjected to
hypoxia. Short-term
hypoxia was used as a model of experimentally induced
amnesia.
2R,4R-APDC given intracerebroventricularly (icv) at doses of 1 mumol and 100 nmol decreased the number of crossings and rearings in the open field, impaired acquisition and consolidation but improved retrieval in the passive avoidance tests. It also shortened the time spent in open arms and prolonged the time spent in closed arms, reduced the number of open and closed arms entries in an elevated "plus" maze, which is a measure of anxiety. Four-minute
hypoxia (2% O(2), 98% N(2)) retrieval of conditioned responses, and exhibited an anxiogenic effect in the elevated "plus" maze in rats, i.e. it reduced the time spent in open arms and the number of entries to closed and open arms.
2R,4R-APDC effect on locomotor and exploratory activity was not changed after
hypoxia, i.e. we observed inhibition of motility. This agonist of II mGluRs used at both doses before
hypoxia significantly improved acquisition and retrieval, and had dual effect on consolidation, viz. at a dose of 1 mumol, it impaired this process and at a dose of 100 nmol it improved it. In the elevated "plus" maze, rats pretreated with
2R,4R-APDC and then subjected to
hypoxia shortened the time spent in open arms and prolonged the time spent in closed arms, reduced the time spent in open arms, i.e. the
drug exhibited anxiogenic effect. We conclude, therefore, that
2R,4R-APDC itself impaired acquisition and consolidation, enhanced retrieval but in rats undergoing
hypoxia, it improved acquisition, retrieval and when used at the dose of 100 nmol enhanced consolidation.
2R,4R-APDC had beneficial effect in
hypoxia-induced memory impairment in passive avoidance test.