CANCELLATION OF LOW-FREQUENCY STIMULATION-INDUCED LONG-TERM DEPRESSION BY DOCOSAHEXAENOIC ACID IN THE RAT HIPPOCAMPUS

The effects of docosahexaenoic acid (DHA) on low-frequency stimulation (LFS)-induced long-term depression (LTD) were investigated in the CA 1 subfield of rat hippocampal slices. LTD was routinely produced by LF S of 900 pulses at 1 Hz. The field excitatory postsynaptic potential ( fEPSP) 40 min after LFS was 59 +/- 4% (n = 18) of baseline response. H owever, in experiments from 18 neurons pretreated with DHA (50 mu M), fEPSP returned to baseline levels within 20 min after LFS in eight cel ls and was slightly potentiated in three cells. Only in seven cells wa s LTD induced. The effect of DHA on LTD was concentration dependent. T he slopes of fEPSP 40 min after LFS were 67 +/- 4% (n = 6), 72 +/- 7% (n = 7) and 80 +/- 5% (n = 18) of baseline response, with pretreatment of 1, 10 and 50 mu M DHA, respectively. The blockade of LTD induction suggests that DHA may play a role in learning and memory. (C) 1998 El sevier Science Ireland Ltd.