Comparative Effects of Heterologous TRPV1 and TRPM8 Expression in Rat Hippocampal Neurons
Figure 6
TRPV1 transfection, but not TRPM8 transfection, alters synaptic transmission.
(A) Fluorescence (left panel) and phase contrast (right panel) images of a single-neuron (autaptic) island in microisland culture transfected with synaptophysin-YFP (Syn-YFP). Scale bar denotes 50 µM. (B) Representative examples of excitatory postsynaptic currents (EPSCs) evoked in transfected autaptic neurons 1 day after transfection. Stimulus artifact has been blanked in each trace for clarity. Note that TRPV1-transfected neurons produced EPSCs with smaller amplitudes than TRPM8-transfected neurons or Syn-YFP-transfected controls. (C) Quantification of average PSC amplitudes for transfected autaptic neurons. Error bars represent SEM. TRPV1-transfected neurons produced significantly smaller evoked PSCs than Syn-YFP-transfected or TRPM8-transfected neurons (ANOVA, p<0.01; Tukey-Kramer method, p<0.01). (D) Percentage of transfected autaptic neurons that did not respond to electrical stimulation with a detectable PSC. When non-responders were analyzed as “failures” from a binomial distribution, the percentage of TRPV1-transfected neurons that successfully responded to stimulation was significantly decreased from YFP-transfected controls (binomial test, p<0.01). Error bars represent SEM based on the binomial distribution.
