AUGMENTED Ca²⁺ MOBILIZATION IS A HYPERTENSIVE TRAIT DISCRIMINATED FROM A ‘MAJOR GENE’ IN BACKCROSS ANALYSIS BETWEEN SHR AND DONRYU RATS

1. Blood pressure and Ca²⁺ mobilization were significantly greater in SHR than in Donryu and F₁ rats. 2. Backcross linkage analysis between spontaneously hypertensive rats and normotensive Donryu rats was performed to dissect polygenic hypertensive traits and to detect the existence of a single ‘major gene’. 3. Cluster and discriminant analysis of a scattergram of blood pressure versus Ca²⁺ mobilization classified the back‐crossed rats into two groups. The two groups were referred to the higher group and the lower group with regard to their relative blood pressure values. 4. Blood pressure was correlated with Ca²⁺ mobilization in each group; the correlation coefficients were 0.41 for the higher group (P < 0.01) and 0.71 for the lower group (P < 0.0001).