The long-term goal of the research is to increase our understanding of how synaptic transmission is modulated and regulated. The proposed research will examine excitatory monosynaptic connections between the A and B neurons in the cerebral ganglion of Aplysia which exhibit a novel form of homosynaptic plasticity, slow developing potentiation (SDP). Brief high frequency stimulation (2 sec at 10-30 Hz) of the presynaptic A neurons induces a synapse-specific increase in synaptic efficacy which can last longer than 20 min. Peak potentiation of the EPSP in the postsynaptic B neuron occurs approximately 5 min after the tetanizing train. The proposed research will elucidate the cellular mechanisms mediating SDP. Voltage clamp recordings will be used to determine the basis for the increase in net inward current during the action potential in the presynaptic neurons after SDP induction. Intracellular drug injection will test whether the phosphatidylinositol (inositol triphosphate/ diacylglycerol) second messenger system and protein kinase C mediate SDP. The role of calcium during SDP induction will be investigated. These studies will generate insights into the cellular mechanisms underlying synaptic plasticity and activity-dependent regulation of synaptic transmission.
Storozhuk, M V; Fredman, S M (1999) Analysis of potentiation in the cerebral ganglion of Aplysia. Neuroscience 91:777-81 |
Fredman, S M (1998) Appearance and maturation of synaptic plasticity during juvenile development in Aplysia. Int J Dev Neurosci 16:483-91 |
Hamilton, J F; Fredman, S M (1998) Characterization of neuronal regeneration in the abdominal ganglion of Aplysia californica. J Neurobiol 35:160-72 |
Fredman, S M (1991) Enhanced synaptic transmission at identified synaptic connections in the cerebral ganglion of Aplysia. Brain Res 562:291-300 |
Hohlfeld, R; Toyka, K; Heininger, K et al. (1988) Anti-nicotinic receptor autoimmunity in myasthenia gravis. Establishment of specific T-helper cell lines and identification of sensitizing epitopes on the alpha-subunit. Monogr Allergy 25:50-67 |
Hohlfeld, R; Toyka, K V; Miner, L L et al. (1988) Amphipathic segment of the nicotinic receptor alpha subunit contains epitopes recognized by T lymphocytes in myasthenia gravis. J Clin Invest 81:657-60 |