Nerve cells fire electrical impulses by the movement of charged ions through the cell membrane. This ionic current flows through specialized protein channels which may be restricted to a specific type of ion e.g. sodium, potassium or calcium. The amount of current carried by a particular ion and the time it occurs during the nerve impulse are important factors in determining normal function of the nervous system. Since many types of ionic channels and subtypes of channels exist in nature, it is essential to understand their diversity and the ways in which each channel is regulated. One possible new type of channel, carrying the "J-current", has been discovered in the lobster. This current is particularly sensitive to the presence of calcium, which may act as a regulator of channel activity. Studying the J-current is important because it is similar to ionic currents found in mammalian brain. The specific aims of this research are: (1) to identify the ion which is responsible for carrying the J-current, (2) to study its relationship to other ionic currents e.g. potassium current, (3) to analyze the effect of certain drugs on the J-current and (4) to determine its physiological role. The data collected by this research may provide insight into the evolution of ionic channels and the function of ionic channels in higher organisms.
