Roles of PLCβ, PIP₂, and GIRK channels in arginine vasopressin‐elicited excitation of CA1 pyramidal neurons

Abstract

Arginine vasopressin (AVP) is a hormone exerting vasoconstrictive and antidiuretic action in the periphery and serves as a neuromodulator in the brain. Although the hippocampus receives vasopressinergic innervation and AVP has been shown to facilitate the excitability of CA1 pyramidal neurons, the involved ionic and signaling mechanisms have not been determined. Here we found that AVP excited CA1

Anti-stress Effect of Octopus Cephalotocin in Rats

“…1b, e, left-shifted red line in d and f, paired t test, *p=0.04). These results are inconsistent with a previous finding [10] suggesting that vasopressin substantially increases the number of APs. Then, CPT was applied to mouse hippocampal CA1 pyramidal neurons in the current clamp mode, and the number of APs was recorded (Fig.…”

“…Avp significantly increased the numbers of APs recorded from hippocampal CA1 pyramidal neurons from 20-to 30-day-old SD rats. An intracellular infusion of GDP-β-S, a nonhydrolyzable G protein, and U73122, a phospholipase C (PLC) inhibitor, does not increase Avp-induced excitability, suggesting that Avp-induced excitability requires PLCβ [10]. In the current study, CPT decreased both the frequency and amplitude of sEPSCs in hippocampal neurons from SD rats.…”

“…Avp modulates social memory via hippocampal Avpr1b-dependent changes [14], increases GABA release and reduces the excitability of hippocampal activity [15]. Avp increases the excitability of SD rat hippocampal neurons by increasing APs [10]. We investigated whether CPT, an Avp analog whose amino acid sequence differs from that of Avp at only the 4 th and 8 th residues, changes excitability in rat hippocampal neurons (Fig.…”

PLCβ-Mediated Depletion of PIP2and ATP-Sensitive K+Channels Are Involved in Arginine Vasopressin-Induced Facilitation of Neuronal Excitability and LTP in the Dentate Gyrus

“…In CA1 pyramidal neurons of the hippocampus, activation of V 1a receptors increases neuronal excitability by inhibition of G protein-gated inwardly rectifying K + (GIRK) channels (Hu et al, 2022), whereas the results in this study indicate that activation of V 1a receptors excites the DG GCs by depressing K ATP channels. The discrepancy may be due to the distinct expression of K ATP channels between CA1 pyramidal neurons and the DG GCs.…”

“…The hippocampus is one of the major biological targets for AVP because high densities of vasopressin receptors have been detected in the hippocampus (Biegon et al, 1984;Brinton et al, 1984;De Kloet et al, 1985;Lawrence et al, 1988) and the hippocampus also receives vasopressinergic innervation (Buijs, 1980;Caffe et al, 1987;Metzger et al, 1993). In line with the distributions of both AVP-containing fibers and AVP receptors in the hippocampus, activation of V 1a receptors excites both pyramidal neurons (Hu et al, 2022) and interneurons (Ramanathan et al, 2012) in the CA1 region. However, the highest densities of AVP receptors (Brinton et al, 1984;De Kloet et al, 1985;van Leeuwen et al, 1987;Campbell et al, 2009), especially the V 1a receptors (Ostrowski et al, 1994;Szot et al, 1994), have been detected in the dentate gyrus (DG), which serves as the gate governing the inflow of information to the hippocampus.…”