We examined the effects of dihydropyridine drugs on evoked neurotransmitter release from cultured neonatal rat sensory and sympathetic neurons. Depolarization with K+-rich solutions increased the release of substance P from cultured sensory neurons. This release was enhanced by BAY K8644 and (+)-202791 and was blocked by a variety of other dihydropyridines including (-)-202791, by Co2+, or in Ca2+-free solutions. K+-rich solutions also stimulated the release of [3H]norepinephrine from cultured sympathetic neurons. This release was also completely blocked by Co2+ or in Ca2+-free solution. In contrast to the situation in sensory neurons, however, the evoked release of [3H]norepinephrine was completely resistant to the blocking effects of dihydropyridine such as nimodipine. However, BAY K8644 was able to enhance the evoked release of [3H]norepinephrine, and this enhancement was blocked by nimodipine. These results are discussed in relation to the possible participation of multiple types of calcium channels in the release of neurotransmitters.
|Original language||English (US)|
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1986|
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