Possible Interaction: Histamine and Potassium

“Summary 1.Shortly after the stimulation by histamine of gastric acid secretion in man there is a consistent and significant rise in the potassium concentration of the gastric contents.”

“ Histamine produced a rise in the potassium , but it was reduced to about one-third the normal magnitude.”

“Histamine hyperpolarized the resting membrane potential of the ON bipolar cells by 5 mV. CONCLUSIONS By enhancing potassium currents in the ON bipolar cells, histamine is expected to reduce the amplitude of the light responses and limit their duration.”

“RESULTS Hi tamine pr oduced a dose-dependent increase in pot assium cu rrents in a subset of bipolar cells.”

“ Potassium concentrations greater than 150 mM produced less histamine release.”

“6 These results indicate that histamine increases the excitability of ferret vagal afferent somata by interfering with two classes of potassium current: the resting or ‘leak’ potassium current (IK(rest)) and the potassium current underlying a post‐spike slow after‐hyper‐polarization (IAHP).”

“Additionally, HA evokes a slow depolarization mediated by a decrease in an inwardly rectifying potassium conductance but is not generated by activation of classically defined HA receptor subtypes.”

“ Histamine reduced or abolished the amplitude of spontaneous transient potassium and chloride currents.”

“In high potassium solution (16.2 mM), 1 microM histamine significantly decreased aiNa by 12.9% from the control of 3.1 +/- 0.2 mM (n = 5, p < 0.05).”

“ Histamine induced a shift in the current-voltage relationship of the potassium background current to the right.”

“SAP was elicited by histamine in a high concentration of potassium solution (27 mmol).”