Hypertension in epileptic mice: a phenomenon related to reduction of Ca(2+)-dependent catecholamine synthesis in the brain.

The possible complication of hypertension and epilepsy was investigated through the response in epileptic El mice. The systolic blood pressure in El mice (male, 8 weeks of age) and that in normal ddY mice (the parent strain of El mice) were compared by a tail-cuff method, using a programmed sphygmomanometer. The systolic blood pressure in El mice (120.5 +/- 5.6 mm Hg) was 28% (P < 0.01) higher than that in ddY mice (93.9 +/- 5.3 mm Hg). The higher systolic blood pressure in El mice was lowered by the acute intracerebroventricular administration of CaCl2 (10 mumol/kg, 30 min before measurement) or dopamine (30 nmol/mouse, 15 min before measurement), and was also improved by the chronic oral supplementation with 1.2% calcium (Ca2+) solution. Combining these results with those in our previous reports, where it is stated that lowering of Ca(2+)-calmodulin-dependent catecholamine synthesis increases the susceptibility to epileptic convulsions, we suggest that the increase in susceptibility to epileptic convulsion and occurrence of hypertension in El mice may be linked and that the two diseases may be associated.