Galanin receptor activation attenuates norepinephrine release from rat spinal cord slices

Galanin and norepinephrine both act on sensory neurons in the rat spinal cord dorsal horn. We looked for the effects of galanin on the basal and electrically-evoked release of [3H]norepinephrine from slices of the dorsal spinal cord. 0.1 to 1.0 microM reduced the basal efflux by maximal 10% and the stimulation-evoked release in a concentration-related manner by maximal 27%. In the presence of 0.1 microM galanin receptor antagonist (M-15) reduction of basal efflux persisted but significant effects on the stimulation-evoked release were no longer observed. The antagonist, given alone, was without effect on the release. Thus galanin can reduce the stimulation-evoked norepinephrine release from spinal cord dorsal horn nerve terminals by an action on galanin receptors, however, the release seems not to be tonically inhibited by galanin.