Several calcium antagonists were screened for their effect on muscarinic acetylcholine receptor-mediated cyclic GMP formation in murine neuroblastoma cells (clone N1E-115). Mn2+, Ni2+, and verapamil rapidly antagonized the response noncompetitively, with the following order of potency: verapamil > Mn2+ > Ni2+. The effects of Mn2+ and Ni2+, but not those of verapamil, were largely reversed by increasing extracellular calcium concentration. Additional effects of these agents included displacement of [3H] quinuclidinyl benzilate binding by verapamil and elevation of cyclic GMP levels by Mn2+ and Ni2+ in the absence of agonists. There results are in support of the hypothesis that receptor-mediated cyclic GMP formation by these cells is dependent upon entry of calcium into the cell and demonstrate the complexity of the effects of calcium antagonists.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Neurochemistry|
|State||Published - 1983|
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience