CALCIUM IMAGING REVEALS NICOTINIC ACETYLCHOLINE-RECEPTORS ON CULTURED MUSHROOM BODY NEURONS

1. We used fluorescence imaging with the visible wavelength indicator fluo-3 to investigate the calcium responses to cholinergic ligands of honeybee Kenyon cells in primary culture. 2. Application of acetylcholine (ACh) or nicotine, but not pilacarpine, promoted a calcium influx into the cell body and neurites. The increase in intracellular calcium after ACh stimulation was blocked by alpha-bungarotoxin. These results support previous histochemical studies that suggested the expression of nicotinic cholinergic receptors on Kenyon cells. 3. After depolarization with high K+ solution fluorescence increased in the somata and neurites, which indicates the presence of voltage-gated Ca2+ channels in Kenyon cell membranes.