| First Author | Park SJ | Year | 2021 |
| Journal | J Neurosci | Volume | 41 |
| Issue | 16 | Pages | 3579-3587 |
| PubMed ID | 33707294 | Mgi Jnum | J:311625 |
| Mgi Id | MGI:6707749 | Doi | 10.1523/JNEUROSCI.2892-20.2021 |
| Citation | Park SJ, et al. (2021) PLCdelta1 Plays Central Roles in the Osmotic Activation of DeltaN-TRPV1 Channels in Mouse Supraoptic Neurons and in Murine Osmoregulation. J Neurosci 41(16):3579-3587 |
| abstractText | The magnocellular neurosecretory cells (MNCs) of the hypothalamus play a vital role in osmoregulation, but the mechanisms underlying MNC osmosensitivity are not fully understood. We showed previously that high osmolality activates phospholipase C (PLC) in rat MNCs in a Ca(2+)-dependent manner and that PLC activation is necessary for full osmotic activation of an N-terminal variant of the TRPV1 (DeltaN-TRPV1) channel. We therefore hypothesized that the Ca(2+)-dependent delta1 isoform of PLC contributes to DeltaN-TRPV1 activation and tested whether MNC function is defective in a transgenic PLCdelta1 KO mouse. Water deprivation for 24 h caused greater increases in serum osmolality and losses in body weight in PLCdelta1 KO mice than it did in control mice. Action potentials and DeltaN-TRPV1 currents were measured in acutely isolated mouse MNCs using whole-cell patch clamp before and after exposure to hypertonic solutions. This treatment elicited a significant activation of DeltaN-TRPV1 currents and an increase in firing rate in MNCs isolated from control mice, but not from PLCdelta1 KO mice. Submembranous filamentous actin was measured in isolated MNCs before and after treatment with angiotensin II and hypertonic solution. Both treatments caused an increase in filamentous actin fluorescence in MNCs isolated from control mice, but both responses were significantly attenuated in MNCs from PLCdelta1 KO mice. Our data demonstrate that the PLCdelta1 isoform plays a key role in the activation of DeltaN-TRPV1 channels and in osmosensory transduction in MNCs. This study advances our understanding of the molecular mechanisms underlying mammalian osmoregulation.SIGNIFICANCE STATEMENT Magnocellular neurosecretory cells (MNCs) of the hypothalamus play a central role in osmoregulation. We have identified a key role for the PLCdelta1 isoform in the activation of DeltaN-TRPV1 channels and osmosensory transduction in MNCs. The data indicate that the PLCdelta1 isoform is activated by the Ca(2+) influx occurring during MNC action potentials and exerts a positive feedback on DeltaN-TRPV1 channels to enhance MNC excitability. This study provides evidence that PLCdelta1 is a key molecule underlying osmosensory transduction, the regulation of VP release, and osmoregulation. |
