Abstract
Prostaglandin (PG) D2 produced in CNS regulates sleep, body temperature and nociception. Although mRNAs of PGD2 receptors were expressed in hippocampus, little is known about how PGD2 affect electrical activities of neurons. In this study, we examined effect of PGD2 application on excitatory synaptic transmission in hippocampal neurons. Whole-cell voltage-clamp recording was made from CA1 pyramidal neurons in slice obtained from mouse hippocampus. Electrical stimulation was delivered to the Shaffer collateral/commissural fibers through a bipolar tungsten electrode with 5 sec intervals, and excitatory postsynaptic currents (EPSCs) were continuously recorded. Main composition of the pipette solution was potassium gluconate, and holding potential was around -70 mV to minimize a contamination of GABA-A receptor mediated IPSC. After puff application of PGD2 (–0.5 μM) variance of EPSC amplitude increased although mean amplitude of EPSCs did not significantly change. Increase in EPSC variance was also observed by application of PGD2 receptor agonist, BW245C. Further results showing that application of PGD2 inhibited depolarization-induced Ca2+ transient, and that change in EPSC variance was not detected in the neurons pretreated with tapsigergin support a view that the PGD2-induced modulation of EPSCs was responsible for deficiency in intracellular Ca2+ mobilization in pre- and/or post-synaptic sites. [J Physiol Sci. 2007;57 Suppl:S153]
