office: 1220 JLNRC
research interests: Synaptic function
Specific Preparations and On-going Projects: a. Using Xenopus nerve-muscle cell cultures, we are studying the properties of synapses. Patch electrode recordings can be made simultaneously from presynaptic varicosities and postsynaptic muscle cells, while reagents can be introduced intracellularly through another electrode on the neuronal cell body. 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 and hyperosmolarity. Both involve presynaptic integrins, tension on which increases either intraterminal calcium or sensitivity to calcium. c. Another project is aimed at understanding the destabilization of ACh receptors in denervated endplates as a nerve reinnervates part of the junction. In addition, I have a long-standing interest in the echolocation capabilities of bats and neural correlates of echolocation.
Kalko, E.K.V., Schnitzler, H.-U., Kaipf, I & Grinnell, A.D., "Hunting and echolocation behavior in Noctilio albiventris: the evolution of piscivory", Behavioral Ecology and Sociobiology, 45 : 305-319 (1998) .
Chen, B.M and Grinnell, A.D., "Kinetics, Ca++ dependence, and biophysical properties of integrin-mediated mechanical modulation of transmitter release from frog motor nerve terminals", J. Neuroscience, 17 : 904-916 (1997) .
Yazejian, B., DiGregorio, D., Vergara, J.L., Poage, R., Meriney, S.D. and Grinnell, A.D., "Direct measurements of presynaptic calcium and calcium-activated potassium currents regulating neurotransmitter release at cultured Xenopus nerve-muscle synapses", J. Neuroscience, 17 : 2990-3001 (1997) .
Grinnell, A. D & Harada, Y., "Specificity and development of the innervation pattern of the Xenopus pectoralis muscle", J. Neurobiol, 31 : 415-432 (1996) .
Harada, Y. and A.D. Grinnell, "Regeneration of specific innervation in the Xenopus pectoralis muscle", J. Neurobiol, 31 : 433-448 (1996) .
Chen, B.M. and Grinnell, A.D., "Integrins help mediate the stretch-induced modulation of transmitter release from frog motor nerve terminals", Science, 269 : 1578-1580 (1995) .
Grinnell, A.D, "Dynamics of nerve-muscle interaction in developing and mature neuromuscular junctions", Physiol. Reviews, 75 : 789-834 (1995) .