Sex diferences in spatial learning and memory and hippocampal long-term potentiation at perforant pathway-dentate gyrus (PP-DG) synapses in Wistar rats

Abstract
Background: Recent studies show that gender may have a signifcant impact on brain functions. However, the
reports of sex efects on spatial ability and synaptic plasticity in rodents are divergent and controversial. Here spatial
learning and memory was measured in male and female rats by using Morris water maze (MWM) task. Moreover, to
assess sex diference in hippocampal synaptic plasticity we examined hippocampal long-term potentiation (LTP) at
perforant pathway-dentate gyrus (PP-DG) synapses.
Results: In MWM task, male rats outperformed female rats, as they had signifcantly shorter swim distance and
escape latency to fnd the hidden platform during training days. During spatial reference memory test, female rats
spent less time and traveled less distance in the target zone. Male rats also had larger LTP at PP-DG synapses, which
was evident in the high magnitude of population spike (PS) potentiation and the feld excitatory post synaptic poten‑
tials (fEPSP) slope.
Conclusions: Taken together, our results suggest that sex diferences in the LTP at PP-DG synapses, possibly contrib‑
ute to the observed sex diference in spatial learning and memory.
Keywords: Long-term potentiation, Hippocampus, Dentate Gyrus, Spatial learning and memory, Sex diference,
Wistar Rat