INTRACELLULAR INJECTION OF INOSITOL 1,4,5-TRISPHOSPHATE INCREASES A CONDUCTANCE IN MEMBRANES OF TURTLE VOMERONASAL RECEPTOR NEURONS IN THE SLICE PREPARATION

Inositol 1,4,5-trisphosphate (IP3) was injected into turtle vomeronasa l receptor neurons in the slice preparation under a whole-cell patch c lamp, and the evoked current was measured. Application of 0.1 mM IP3 e voked a prolonged, inward current (52 of 98 neurons) with an average p eak amplitude of 89.9 +/- 10.9 pA. The reversal potential of the respo nse induced by IP3 was estimated to be -32.3 +/- 1.5 mV (6 neurons). B athing the neurons in 10 mu M ruthenium red solution greatly reduced t he IP3 evoked inward current to 18.0 +/- 4.6 pA (5 neurons). This is t he first study to demonstrate that the membranes of the turtle vomeron asal neurons carry IP3-activated conductance.