Histamine H₁ receptor binding capacities in the amygdalas of the amygdaloid kindled rat

The histamine H₁ receptor binding capacity of the amygdalas of amygdaloid kindled rats was studied. In the kindled nonstimulated amygdala, significant decrease in K(D) and B(max) values compared with those of control amygdala were found 1 week after the last kindled seizure. One month after the last kindled seizure, the decreased K(D) value was sustained in the kindled nonstimulated amygdala. This decreased B(max) value 1 week after the last kindled seizure in nonstimulated amygdala seizure susceptibility. The decreased K(D) value in nonstimulated amygdala observed until 1 month after the last kindled seizure indicated the long-lasting increment of binding affinity of the pyrilamine binding site of the histamine H₁ receptor in the steady state of kindled seizure susceptibility.