XXXX influx into dendrites of the leech Retzius neuron evoked by @entity750 .

@entity3007 @entity268 @entity3858 @entity515 @entity15404 @entity750 @entity8279 @entity141 @entity460
@entity750 ( @entity750 ) is a ubiquitous neurotransmitter and neuromodulator that affects neural circuits and behaviours in vertebrates and invertebrates. In the present study, we have investigated @entity750 -induced @entity141 transients in subcellular compartments of Retzius neurons in the leech central nervous system using confocal laser scanning microscopy, and studied the effect of @entity750 on the electrical coupling between the Retzius neurons. Bath application of @entity750 (50mM) induced a @entity141 transient in axon, dendrites and cell body of the Retzius neuron. This @entity141 transient was significantly faster and larger in dendrites than in axon and cell body, and was half-maximal at a @entity750 concentration of 5-12mM. The @entity141 transient was suppressed in the absence of extracellular @entity141 and by @entity3858 (100mM), a non-specific antagonist of metabotropic @entity750 receptors, and was strongly reduced by bath application of the @entity141 channel blocker @entity515 (2mM). Injection of the non-hydrolysable @entity3007 analogue GTPgammaS increased and prolonged the dendritic @entity750 -induced @entity141 transient. The non-selective protein kinase inhibitor H7 (100mM) and the adenylate cyclase inhibitor @entity15404 (500 mM) did not affect the @entity141 transient, and the membrane-permeable @entity268 analogue @entity8279 (500 mM) did not mimic the effect of @entity750 application. @entity750 reduced the apparent electrical coupling between the two Retzius neurons, whereas suppression of the @entity141 influx by removal of external @entity141 improved the transmission of action potentials at the electrical synapses which are located between the dendrites of the adjacent Retzius neurons. The results indicate that @entity750 induces a @entity141 influx through @entity460 channels located primarily in the dendrites, and presumably activated by a G protein-coupled @entity750 receptor. The dendritic @entity141 increase appears to modulate the excitability of, and the synchronization between, the two Retzius neurons.
