Orexin-A inhibits γ-aminobutyric acid current of neonatal rat spinal cord ventral horn neurons by activating OX < sub > 1 < /sub > R, OX < sub > 2 < /sub > R and Ca < sup > 2+ < /sup > -independent PKC

Nan Fang Yi Ke Da Xue Xue Bao. 2021 May 20;41(5):694-701. doi: 10.12122/j.issn.1673-4254.2021.05.09.ABSTRACTOBJECTIVE: To investigate the effect of orexin-A on the functionality of ionotropic γ-aminobutyric acid (GABA) receptors in spinal cord ventral horn neurons and its mechanisms.OBJECTIVE: The spinal cord containing the lumbosacral enlargement was isolated from neonatal SD rats (7-12 days old) and sliced. The slices were digested with papain (in 0.18 g/30 mL artificial cerebrospinal fluid) for 40-60 min, and the ventral horn neurons were separated acutely using fire-polished Pasteur pipettes. After the cells adhered to the bottom of Petri dishes, patch-clamp experiments combined with pharmacological methods were performed to test the effects of orexin-A on GABA currents of the neurons treated with SB334867 (a selective OX1R antagonist), TCSOX229 (a selective OX2R antagonist), Bis-Ⅳ (a PKC inhibitor), PMA (a PKC agonist), Rp-cAMP (a PKA inhibitor), or BAPTA (Ca2+ chelator).OBJECTIVE: The isolated neurons maintained good morphologies with diverse shapes of cell body and long protrusions. Treatment with orexin-A significantly inhibited the amplitude of GABA-induced current (P < 0.001, n=49) with an inhibition rate of (67.48±12.50)%. SB334867 and TCSOX229, when applied simultaneously, completely abolished the suppressive effect of orexin-A on the GABA currents (P=0.93, n=6), and their separate use partially relieved the suppressive effect of orexin-A (P=0.001, n=8; P=0...
Source: Journal of Southern Medical University - Category: Universities & Medical Training Authors: Source Type: research