Related Experiment Videos
Membrane currents evoked by histamine in rabbit basilar artery
M Kamouchi1, R Ogata, M Fujishima
1Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
The American Journal of Physiology
|February 1, 1997
Summary
Histamine activates an inward current in rabbit basilar artery smooth muscle cells, likely via H1 receptors and chloride channels. This current may involve calcium signaling and influence calcium influx.
Area of Science:
- Physiology
- Pharmacology
- Cellular Electrophysiology
Background:
- Histamine is a key mediator in vascular function.
- Smooth muscle cell ion channel activity is crucial for regulating vascular tone.
Purpose of the Study:
- To investigate the membrane currents evoked by histamine in isolated rabbit basilar artery smooth muscle cells.
- To elucidate the ionic mechanisms and receptor subtypes involved in histamine-induced currents.
Main Methods:
- Perforated-patch voltage-clamp technique was employed.
- Isolated smooth muscle cells from rabbit basilar artery were used.
- Pharmacological agents (charybdotoxin, niflumic acid, pyrilamine, cimetidine) and ionic manipulations (Cl-, Ca2+) were utilized.
Main Results:
- Histamine (10 microM) induced a transient inward current at -60 mV and an outward current at more negative potentials.
- The inward current was blocked by niflumic acid and pyrilamine (H1 receptor antagonist), but not cimetidine (H2 antagonist).
- Histamine-induced inward current was dependent on extracellular Ca2+ and potentially involved Cl- currents, possibly linked to intracellular Ca2+ elevation.
Conclusions:
- Histamine activates an inward current in rabbit basilar artery smooth muscle cells primarily through H1 receptors.
- The inward current is likely mediated by chloride ions and influenced by intracellular calcium levels.
- This histamine-induced current may play a role in regulating calcium influx and smooth muscle contraction.