Figure 1.

Lactacystin blocked FMRFa-induced LTD of sensorimotor synapse. A1, B1, Bright-field images of sensorimotor cocultures. MN, Motor neuron; SN, sensory neuron. A2, B2, Sensory neurons filled with Alexa 488-dextran, indicating successful injection of DMSO (A2) or lactacystin (B2). A3, B3, Examples of EPSPs measured before the presynaptic injection (pre) and 24 h after treatment with FRMFa (post). EPSPs were elicited by extracellular stimulation of the sensory neuron. C, For statistical analysis, the ratio of post over pre EPSP amplitude was formed for each coculture. *p < 0.01. D, E, Examples of EPSPs measured before (pre) and ∼24 h after (post) presynaptic injection of DMSO (vehicle) or lactacystin. F, Lactacystin did not significantly affect synaptic strength over a 24 h period (p = 0.54). Error bars indicate SEM.