POTENTIATION OF PHOSPHOINOSITIDE-DERIVED SIGNALS DURING LTP IN INTACTRAT-BRAIN

IN order to examine the relationship between long-term potentiation (L TP) and phosphoinositide (PI) turnover, we evaluated these throughout anesthetized rat brain using carbon-11-labeled diacylglycerol (C-11-DA G). High-frequency tetanic stimulation (400 pulses at 400 Hz) to the p erforant pathway induced LTP in rat dentate gyrus. In autoradiograms o f rat brains, LTP was associated with the occurrence of multiple highl y radioactive spots in many regions distant from the stimulated site. Following i.v. administration of an NMDA receptor antagonist prior to stimulation, however, no high-density spots were found. These findings directly demonstrate that potentiation of phosphoinositide-derived si gnaling was induced during LTP, and the finding of multiple location s uggests the occurrence of polysynaptic neurotransmission through neura l networks pertaining to learning and memory. (C) 1998 Rapid Science L td.