Long-Lasting Latent Action of Colchicine

�Electron micrographs of sections of the labellar chemosensillaof the blowfly, Phormia regina, showed that treatment with sodium deoxycholate (DOC ; 7 .2 mM for 2 min) destroyed the distal processes of the receptors from up to 10 Am from the tip of the sensillum, but these processes regenerated almost completely within 0.5 h. However, when DOC treatment was preceded by colchicine treatment (25 mM for 2 min), >10 h was required for complete regeneration . Sugar receptor responses supported these findings and disclosed a more detailed time course of regeneration after DOC treatment: without colchicine pretreatment, the destroyed distal process completely regenerated in 0.3-1 .0 h, but with pretreatment, regeneration began at 3 h and reached the chemosensillar tip at 8 h at the earliest . Hardly any depression of the response was observed for 8 h after treatment with colchicine alone, but a transient depression was detected at 12 h . Based on these results, the role of microtubules in the maintenance of the receptor membrane is discussed .