Stress and brain histaminergic system: effects of weak electric foot-shock.

A weak electric foot-shock stressful stimulus (0.5 mA x 1 s x 5 times) significantly increases plasma corticosterone (CS) levels and modifies [3H]-histamine ([3H]-HA) binding site constants related to H2 receptors in rat cortical membranes. Progressive and total recovery of basal binding characteristics occurs 90 min later. A double-foot-shock stress procedure delays [3H]-HA binding characteristic recovery instead of strengthening stress effects. This finding is further evidence of involvement of the brain's histamine receptors in the response to mild stress.