TY - JOUR T1 - Roles of biogenic amines in regulating bioluminescence in the Australian glowworm Arachnocampa flava JF - JOURNAL OF EXPERIMENTAL BIOLOGY Y1 - 2011 DO - 10.1242/jeb.060509 A1 - Rigby, Lisa M. A1 - Merritt, David J. SP - 3286 EP - 3293 KW - dopamine KW - light organ KW - neuroanatomy KW - octopamine KW - serotonin KW - tyramine AB - The glowworm Arachnocampa flava is a carnivorous fly larva (Diptera) that uses light to attract prey into its web. The light organ is derived from cells of the Malpighian tubules, representing a bioluminescence system that is unique to the genus. Bioluminescence is modulated through the night although light levels change quite slowly compared with the flashing of the better-known fireflies (Coleoptera). The existing model for the neural regulation of bioluminescence in Arachnocampa, based on use of anaesthetics and ligations, is that bioluminescence is actively repressed during the non-glowing phase and the repression is partially released during the bioluminescence phase. The effect of the anaesthetic, carbon dioxide, on the isolated light organ from the present study indicates that the repression is at least partially mediated at the light organ itself rather than less directly through the central nervous system. Blocking of neural signals from the central nervous system through ligation leads to uncontrolled release of bioluminescence but light is emitted at relatively low levels compared with under anaesthesia. Candidate biogenic amines were introduced by several methods: feeding prey items injected with test solution, injecting the whole larva, injecting a ligated section containing the light organ or bathing the isolated light organ in test solution. Using these methods, dopamine, serotonin and tyramine do not affect bioluminescence output. Exposure to elevated levels of octopamine via feeding, injection or bathing of the isolated light organ indicates that it is involved in the regulation of repression. Administration of the octopamine antagonists phentolamine or mianserin results in very high bioluminescence output levels, similar to the effect of anaesthetics, but only mianserin acts directly on the light organ. L2 - 48289 L3 - 49489 PB - {COMPANY OF BIOLOGISTS LTD} CY - {BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND} VL - 214 ER -