1. 1. The effects of pressure on synaptic currents were examined in crayfish abdominal muscles. 2. 2. Helium pressure (10.1 MPa) considerably decreased extracellulariy-recorded excitatory junctional potentials associated with increased short-term facilitation. 3. 3. These effects could be mimicked by a reduction of [Ca2+]o, and partially compensated by an increase in [Ca2+]o. 4. 4. Pressure also reduced the amplitude of the extracellular nerve terminal potentials (ENTP) by up to 25%, and significantly increased synaptic delay in a [Ca2+]o-dependent manner. 5. 5. The interaction between compression and various [Ca2+]o were analysed in terms of an existing model of transmitter release. The results were consistent with the hypothesis that high pressure decreases the maximal Ca2+ influx into nerve terminals. 6. 6. The decreased ENTP and increased synaptic delay suggest that additional processes may be involved in pressure effects on synaptic transmission.
|Number of pages||6|
|Journal||Comparative Biochemistry and Physiology -- Part A: Physiology|
|State||Published - 1 Jan 1992|