Expression profile of the pore-forming subunits α1A and α1D in the foetal bovine hypothalamus: a mammal with a long gestation.

This study describes the expression of the voltage operated calcium channels (VOCCs) subunits α1A (typical of the P/Q family) and α1D (of the L family) in the bovine hypothalamus. The expression of both P/Q and L families has been characterized in the brain of adult mammals. However, their distribution and expression during foetal neuronal differentiation have not yet been determined. The expression profile of the α1A and α1D pore-forming subunits was investigated during four embryonic stages in bovine foetuses. Our data suggest that the expressions of α1A and α1D are correlated during development, with an increase only in males that peaks on the last period of gestation. Bovine male hypothalami showed significantly higher α1A and α1D expression values in comparison to female ones during the whole developmental period. In the females, the expression profiles of both genes were constant during all the developmental time. Immunohistochemical studies confirmed the presence of the α1A and α1D protein subunits in foetal hypothalamic neurones starting from the third foetal stage. Our data provide new information on the hypothalamic expression of α1A and α1D subunits during development in a mammal with a long gestation period and a large and convoluted brain.