Measurement of [³H]PN200-110 and [¹²⁵I]ω-conotoxin MVIIA binding

Intracellular Ca(2+) ([Ca(2+)](i)) can rise primarily via release from intracellular storage sites (e.g., the endoplasmic reticulum) or via entry across the membrane down the steep concentration gradient. Ca(2+) can enter through two main classes of plasma membrane-located Ca(2+) channels: receptor operated and voltage sensitive. Voltage-sensitive Ca(2+) channels are involved in a wide and diverse array of physiological responses including neurotransmitter release. In addition, many guanine nucleotide protein (G) coupled receptors couple to voltage-sensitive Ca2(+) channels to reduce Ca(2+) influx.