| The frontal ganglion (FG) is an important regulator of feeding behavior in insects. Three large neurons in the FG of the tobacco hornworm, Manduca sexta, contain nitric oxide synthase (NOS), the enzyme that synthesizes nitric oxide (NO). This small molecule has been implicated as a neurotransmitter with a variety of functions in insects. To determine whether NO plays a role in regulating movement of the gut in Manduca, I used extracellular recording to assess the effect of the NO donor NOC7 on the frontal and recurrent nerves (RN and FN, respectively), as well as on the esophageal constrictor (EC) muscle. I also employed intracellular recording to investigate the production of NO within the FG. My work demonstrated that NOC7 can stimulate activity of the RN, FN, and EC, although there was substantial variability in the responses. At least one of the NO-generating cells in the FG utilizes Ca2+ spikes. |
