[L-glutamate-activated membrane conductance of spinal cord nerve cells during the early embryogenesis of the chicken]

Transient and steady-state L-glutamate-activated membrane currents were investigated by means of intracellular perfusion, voltage clamp techniques and concentration clamp in spinal cord neurons of 6-11 day chick embryos. The Hill coefficient was found to equal 1 for transient and 2 for steady-state components. Concentration of L-glutamate evoking half effect decreased during development more than 10 times for the steady-state component whereas it remained constant for the transient component. Existence of two types of glutamate-activated receptors in the membrane of spinal cord neurons at early stages of embryonic development is supposed.