ラット分界条床核２型神経細胞の興奮性に対するニューロテンシンの効果に関与する細胞内情報伝達

抄録

The effects of neurotensin (NTS) on the excitability of type II neurons in the rat dorsolateral bed nucleus of the stria terminalis (dlBNST) were examined using whole-cell patch-clamp electrophysiology. Bath-application of NTS depolarized type II dlBNST neurons. Analyses of the steady-state I–V relationships implied that the depolarizing effect of NTS is due to potassium conductance blocking. The depolarizing effect of NTS was abolished in the presence of a PLC inhibitor, but not affected by a protein kinase C inhibitor. In the presence of a CaMKII inhibitor, NTS showed depolarizing effects via the increase in non-selective cation conductance in addition to the decrease in potassium conductance. Unexpectedly, in the presence of a PKA inhibitor, NTS hyperpolarized type II dlBNST neurons. These results reveal that diverse signaling pathways mediate the effects of NTS on the excitability of type II dlBNST neurons. The possible intracellular signaling mechanism is that activation of the Adenylate cyclase-cAMP-PKA pathway exerts depolarizing effects on type II dlBNST neurons by decreasing potassium conductance and increasing non-selective cation conductance, whereas activation of the CaMKII pathway exerts hyperpolarizing effects on dlBNST neurons by decreasing non-selective cation conductance.