Effects of dauricine and tetrandrine on [3H] WEB 2086 specific binding to bovine anterior cerebral arterial smooth muscle cells in vitro.

By using [3H] WEB 2086, a PAF antagonist, specific binding sites of PAF on bovine anterior cerebral arterial smooth muscle cells was identified. Two populations of binding sites with different dissociation constants on the cells were found. The Kd-1 = 22.8 +/- 5.0 nmol.L-1, Kd-2 = 186 +/- 20.5 nmol.L-1 at 25 C. The total number of binding sites were Bmax-1 = 2.1 +/- 0.3 pmol/10(6) cells and Bmax-2 = 12.1 +/- 1.5 pmol/10(6) cells. Dauricine and tetrandrine, two active compounds with similar chemical structure extracted from traditional Chinese herbs, were found to inhibit [3H] WEB 2086 specific binding significantly in culture cells.