Femtosecond lasers for synaptic transmission research

Del Mar Photonics' field engineer installs Trestles Finesse femtosecond laser at the Department of Anesthesia, Cincinnati Children's Hospital Medical Center. Assistant Professor David Richards briefly describes his research on synaptic transmission.


Vesicular release mode shapes the postsynaptic response at hippocampal synapses 1. David A. Richards1

+ Author Affiliations 1. 1Department of Neurology, University of Cincinnati, Vontz Center for Molecular Studies, 3125 Eden Ave, Cincinnati, OH 45267, USA 1. Corresponding author D. A. Richards: Department of Neurology, University of Cincinnati, Vontz Center for Molecular Studies, 3125 Eden Avenue, Cincinnati, OH 45267, USA.

Abstract

Release of neurotransmitters from synaptic vesicles is a central event in synaptic transmission. Recent evidence suggests that synaptic vesicles fuse with the plasma membrane by multiple routes during exocytosis, but the regulation and physiological implications of this choice are unclear. At hippocampal synapses, two modes of synaptic vesicle exocytosis can be distinguished by virtue of the rate and extent of loss of a fluorescent lipid marker (FM1-43). Here these two modes of exocytosis were investigated with a combination of electrophysiological recording and fluorescence imaging. It is shown that these exocytic modes result in distinct postsynaptic consequences, such that so-called kiss-and-run' exocytosis results in negligible activation of AMPA receptors, compared to the robust postsynaptic responses elicited by apparent full fusion. In contrast NMDA receptors are robustly activated by this form of glutamate delivery. Addition of cyclothiazide, which blocks AMPA receptor desensitization, reveals that the relatively slow rate of release of glutamate during kiss-and-run exocytosis shifts the population of AMPA receptors into a desensitized state, rather than simply being insufficient for receptor activation. These findings provide further support for the existence of a fusion pore mediated mode of exocytosis, and demonstrate that these two exocytic modes directly affect the throughput of synaptic transmission.

Category:

Science & Technology

Tags:

• neurotransmitters
• synaptic
• vesicles
• plasma
• membrane
• exocytosis
• physiological
• hippocamp
• vesicle
• fluorescent
• lipid
• marker
• FM1-43
• electrophysiological
• recording
• imaging

[malekb88]

Seems like some very interesting research you're undertaking. Best of luck and looking forward to reading the results of your studies