Regulation of cyclic GMP elevation in the developing antennal lobe of the sphinx moth, Manduca sexta

In the moth, Manduca sexta, 3',5'-guanosine monophosphate (cGMP) is transie ntly elevated during adult development in about 100 neurons of the antennal lobe. We demonstrate that nearly all of these neurons are local interneuro ns of the lateral cluster I, that their capacity to show a strong cGMP resp onse during development is regulated by the steroid hormone 20-hydroxyecdys one, and that in a subpopulation of these neurons cGMP elevation seems to b e controlled directly by the gaseous messenger molecule nitric oxide (NO). Treatment with the acetylcholine esterase inhibitor eserine, antennal nerve transection, and electrical stimulation of the antennae suggest that NO/cG MP signaling during development is an activity-de pendent process. Besides input from the antennae, input from the central brain and the ventral gangl ia is involved in upregulating cGMP in the antennal-lobe neurons, Possible sources are centrifugal aminergic neurons, since application of serotonin a nd histamine enhances the GMP signal in local interneurons. Comparing the t ime course of cGMP elevation with events occurring during development leads us to the hypothesis that the NO/cGMP signaling pathway might be involved in synapse formation of a subset of antennal-lobe neurons. (C) 1999 John Wi ley & Sons, Inc.