Preliminary Experiments Suggest Cytochalasin H Decreases Synaptic Transmission at the Crayfish Neuromuscular Junction

Abstract

The chemical Cytochalasin J has been demonstrated to interfere with actin composed microfilaments involved in mitosis. Through the application of Cytochalasin H, chemically similar to Cytochalasin J, we endeavored to demonstrate both the role of presynaptic microfilaments in and the influence of Cytochalasin H on a relatively unexplored chemical on EPSPs in Crayfish. We conducted two separate trials, both times using DMSO in the control and the experimental solutions. The concentration of DMSO in the first trial was 1:100, with the Cytochalasin test at 10?g/ml. The second trial doubled both the concentration of DMSO and Cytochalasin, bringing them to 1:50 and 20?g/ml respectively. Due to a limited supply of Cytochalasin, we used 7.5ml of solution throughout the experiments. The control in thefirst trial had an average EPSP amplitude of 39.6 +/- 5.2mV S.D., while the experimental had an average of 27.6 +/- 7.7mV S.D. During the higher concentration second trial, the control had an average EPSP amplitude of 57.5 +/- 13.6mV S.D., while the experimental averaged 64.5 +/- 3.2mV S.D. A t-test on the data from the first trial showed that there is a 2% chance that the change in EPSP magnitudes was due to natural variance, while a test on the second trial indicated a chance of 36%. Although preliminary in nature, this data indicates that Cytochalasin H may have an effect on glutamatergic synapses. A glutamate test following the application of Cytochalasin indicated that Cytochalasin H affects the presynaptic terminal, which suggests actincomposed microfilaments are involved in the release of neurotransmitters at the synaptic junction.