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Updated: Aug 7, 2026

Microelectrode Impalement Method to Record Membrane Potential from a Cannulated Middle Cerebral Artery
Published on: July 2, 2019
Serotonin depolarizes the membrane potential in rat mesenteric artery myocytes by decreasing voltage-gated K+
Young Min Bae1, Aeran Kim, Junghwan Kim
1Artificial Muscle Research Center, College of Medicine, Konkuk University 322 Danwol-dong, Choongju 380-701, Republic of Korea. ymbae30@kku.ac.kr
Abstract:
We hypothesized that voltage-gated K+ (Kv) currents regulate the resting membrane potential (Em), and that serotonin (5-HT) causes Em depolarization by reducing Kv currents in rat mesenteric artery smooth muscle cells (MASMCs). The resting Em was about -40 mV in the nystatin-perforated patch configuration, and the inhibition of Kv currents by 4-aminopyridine caused marked Em depolarization. The inhibition of Ca2+-activated K+ (KCa) currents had no effect on Em. 5-HT (1 microM) depolarized Em by approximately 11 mV and reduced the Kv currents to approximately 63% of the control at -20 mV. Similar 5-HT effects were observed with the conventional whole-cell configuration with a weak Ca2+ buffer in the pipette solution, but not with a strong Ca2+ buffer. In the presence of tetraethylammonium (1mM), 5-HT caused Em depolarization similar to the control condition. These results indicate that the resting Em is largely under the regulation of Kv currents in rat MASMCs, and that 5-HT depolarizes Em by reducing Kv currents in a [Ca2+]i-dependent manner.
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