Figure 1: C.elegans displays sensory-induced feeding facilitation and suppression.

(a,b) Diacetyl, isoamylol and quinine modulate the pumping rate in a concentration-dependent manner. (c) Time courses of action of diacetyl, isoamylol and quinine on modulating pumping rate. (d) Diacetyl-induced feeding facilitation requires odour sensation through AWA neurons. The pumping rate of various strains was measured under the same conditions and normalized to that of wild-type (WT; N2) animals. Mutation of AWA diacetyl receptor odr-10 and AWA developmental gene odr-7 eliminated the enhancement of pumping rate induced by exposure to 100% diacetyl on food. (e) Quinine-induced feeding suppression requires ASH neurons through its receptor QUI-1 and glutamate signalling. Normalized pumping rates under control and 5 mM quinine feeding conditions are shown. (f) Isoamylol-induced feeding suppression requires ASH neurons through OSM-9 and glutamate signalling. Normalized pumping rates under control conditions and with exposure to 100% isoamylol in food are shown. Dia, diacetyl; Iso, isoamylol; Qui, quinine. The feeding rates of N2 animals used for normalization in a–f are 238, 248, 247, 250, 248 and 263 pumps per min, respectively. Statistics (d–f): *P<0.05, **P<0.01, ***P<0.001 (Student's t-test). Data are averaged from 10 to 12 animals for each condition. Error bars represent s.e.m.