Identification of the neuronal effects of ethanol on C. elegans by in vivo fluorescence imaging on a microfluidic chip.

ABSTRACT

Caenorhabditis elegans (C. elegans) is a well-established model organism for investigating the correlations between behavioral and neuronal activities. Here, we demonstrated a microfluidic-based method that allowed stimulation-based neuronal analysis of immobilized C. elegans for identifying the neuronal effects of ethanol on the chemosensory responses of the right ASE (ASER) neuron. A one-piece microvalve was developed for the immobilization of C. elegans. Stimulations were realized by interface shifting of laminar flows. Well-fed transgenic worms expressing the calcium indicator G-CaMP in ASER neurons were used for in vivo fluorescence imaging. To evaluate the developed method, we first studied the effects of ethanol on the ASER neurons in response to a single NaCl stimulus. Results indicated that ethanol acutely suppressed the ON responses of ASER neurons to NaCl rather than the OFF response. Further studies of the adaptation of ASER neurons in response to NaCl and in the presence of ethanol suggested that ethanol interfered with the adaptation of neurons. The developed method exhibited the advantages of ease of operation and high throughput. We expect this new method to open up a new avenue for investigating the correlations between the behavioral and neuronal activities of C. elegans.