Abstract:

Objective     To introduce a method of whole-cell patch clamp recording from arteriolar segments. Methods    Whole-cell patch clamp recordings were performed on smooth muscle cells (SMCs) in situ of isolated segments from guinea pig spiral modiolar arteries (SMA), anterior inferior cerebellar artery(AICA) branches and mesenteric artery(MA) branches (<100μm in diameter). Results     The mean resting membrane potential of the three arterioles ranged from -25mV to -37mV, while  the mean membrane capacitance (Cinput)of the three arterioles ranged from 70pF to 250pF, and both were much higher than those of the isolated single smooth muscle cell. After application of the gap junction blocker DPBA (100μmol/L),  membrane resistance (Rinput) of cells in situ was (4937±741) MΩ(n=12), (3703±367) MΩ(n=8) and (3336±479) MΩ(n=12) in SMA, AICA and MA segments, respectively. The Cinput was (4.5±0.2) pF (n=9), (7.1±0.7) pF (n=5) and (9.6±0.9) pF (n=7), respectively. Both Rinput and Cinput were much closer to those of the isolated single smooth muscle cell, suggesting that gap junctions existed between cells of the arterioles. Conclusion     Whole-cell patch clamp recording from cells in situ of arteriolar segments is potentially useful in the study of intercellular gap junctions and the mechanisms underlying the actions of neurotransmitters and drugs on arterioles.

Key words: Arteriole; Gap junction; Patch clamp; Smooth muscle cells