Accession Number : ADA187059

Title :   Biophysical and Biochemical Mechanisms in Synaptic Transmitter Release.

Descriptive Note : Annual rept. 1 Sep 86-31 Aug 87,

Corporate Author : NEW YORK UNIV MEDICAL CENTER N Y

Personal Author(s) : Llinas, Rodolfo R

PDF Url : ADA187059

Report Date : 28 Sep 1987

Pagination or Media Count : 13

Abstract : Four major goals were accomplished in the second year. Two related to synapsin I regulation of transmitter release and two related to the temperature dependence of the synaptic release process with a preliminary study of quantal release at the squid giant synapse. The results may be summarized as follows: (1) Demonstration that the dephosphorylated tail fragments of synapsin I do not regulate synaptic release which excludes the possibility that tail fragments themselves can prevent vesicular release. (2) Injection of head phospho synapsin I does not regulate synaptic release, demonstrating that the molecule itself does not interfere with vescular fusion. These two experiments indicate that synapsin I works by affixing the synaptic vesicles to the cytoskeletal system. (3) Video-enhanced microscopy results demonstrated that axoplasmic mobility is not altered by either tail fragments or head phospho synapsin I, confirming the findings obtained by the electrophysiological study. The results demonstrate the mechanism by which synapsin I regulates transmitter release. A study of the temperature dependence of transmitter release demonstrated that temperature can be used to study the kinetics of synapsin I inhibition of transmitter release. Measurements of miniature potentials were finally accomplished routinely and can now be utilized as a technique to determine directly the effect of synapsin I on single vesicular fusion. Keywords: Electrophysiology, Biochemistry, Optical Measurements, Calcium current.

Descriptors :   *ELECTROPHYSIOLOGY, *SYNAPSE, *NERVE TRANSMISSION, BIOCHEMISTRY, BIOPHYSICS, CALCIUM, FRAGMENTS, INJECTION, MEASUREMENT, OPTICAL PROPERTIES, TEMPERATURE, POTENTIAL ENERGY, POTENTIOMETRIC ANALYSIS

Subject Categories : Biochemistry
      Biology

Distribution Statement : APPROVED FOR PUBLIC RELEASE