N6-cyclohexyladenosine inhibits veratridine-stimulated 22Na uptake by rat brain synaptosomes

The effect of the stable adenosine analogue, N6-cyclohexyladenosine, on 22Na uptake by rat brain synaptosomes stimulated by veratridine was investigated. In the presence of N6-cyclohexyladenosine, both the initial rate and the maximum sodium uptake were decreased. The inhibitory effect of N6-cyclohexyladenosine on sodium uptake by synaptosomes after 5 s of incubation with 22Na was concentration-dependent, antagonized by 1,3-dipropyl-8-p-sulfophenylxanthine, and attenuated by increasing the concentration of veratridine. The possibility that the adenosine analogue, by activating a xanthine-sensitive adenosine receptor, can operate inhibition of the voltage-dependent sodium channels is discussed.