Alan Grinnell

Adaptations of the auditory nervous system of echolocating bats that enable them to orient and hunt using echoes of emitted sounds as a substitute for vision. Also, bat echolocation behavior and feeding strategies. Trophic influences between nerve and muscle governing number, size and strength of nerve terminals. Regulation of neurotransmitter release and properties of presynaptic active zones.
Specific Recent Projects: a. Using Xenopus nerve-muscle cell cultures, patch electrode recordings can be made simultaneously from presynaptic varicosities and postsynaptic muscle cells. Large conductance Ca2+-dependent K+ (BK) channels that co-localize with Ca2+ channels at presynaptic active zones (AZs) can be used to report [Ca2+] at AZs and correlate this direct measurement with neurotransmitter release. This allows correlation of ionic currents with transmitter release and modulation of release, and analysis of molecular mechanisms of release. b. Using mature frog neuromuscular preparations, we are studying the mechanisms of regulation of transmitter release efficacy by muscle stretch, mediated by integrins. c. Using an old world flying fox bat that has excellent night vision but also has evolved good echolocation, we are attempting to determine whether they can shift seamlessly from one modality to the other. I also have a long-standing interest in the art and iconography of preColumbian ceramics from Central Panama.