Title: | Perfusion with cAMP analogue affects pheromone-sensitive trichoid sensilla of the hawkmoth Manduca sexta in a time-dependent manner |
Author(s): | Flecke C; Nolte A; Stengl M; |
Address: | "Biologie, Tierphysiologie, Philipps-Universitat Marburg, 35032 Marburg, Germany" |
ISSN/ISBN: | 1477-9145 (Electronic) 0022-0949 (Linking) |
Abstract: | "Octopamine causes time-dependent disadaptation of pheromone-sensitive olfactory receptor neurons (ORNs) of Manduca sexta. Because the majority of insect octopamine receptors are positively coupled to adenylyl cyclases we examined whether cyclic adenosine monophosphate (cAMP) mimics octopamine-dependent modulation of pheromone transduction in a time-dependent manner. Long-term tip recordings of single trichoid sensilla of Manduca sexta were performed during three zeitgeber times (ZTs, ZT 0=lights on), while stimulating the sensilla with two doses of the main pheromone component bombykal in a non-adapting protocol. The membrane-permeable cAMP analogue 8bcAMP increased the normalized sensillar potential amplitude in a time- and bombykal dose-dependent way. At the higher bombykal dose only, the applied 8bcAMP antagonized an endogenous decrease in the mean sensillar potential amplitude at ZT 1-4 and ZT 8-11 when ORNs were adapted but not at ZT 22-1, when ORNs were sensitized. In contrast to octopamine, 8bcAMP did not consistently affect the initial pheromone-dependent action potential frequency, the phasic/tonic response pattern, or the time-dependent shift to lower mean action potential frequencies at ZT 8-11. Furthermore, 8bcAMP increased the spontaneous action potential frequency time dependently, but differently from octopamine. In conclusion, our results show that cAMP only partly mimics the octopamine-dependent disadaptation of olfactory receptor neurons during photophase, apparently due to another missing octopamine-dependent synergistic factor such as defined intracellular calcium levels" |
Keywords: | 8-Bromo Cyclic Adenosine Monophosphate/*pharmacology Action Potentials/drug effects/radiation effects Alkadienes/pharmacology Animals In Vitro Techniques Light Male Manduca/*drug effects/*physiology/radiation effects Octopamine/pharmacology Olfactory Rece; |
Notes: | "MedlineFlecke, Christian Nolte, Andreas Stengl, Monika eng Research Support, Non-U.S. Gov't England 2010/02/16 J Exp Biol. 2010 Mar 1; 213(5):842-52. doi: 10.1242/jeb.032839" |