Abstract

The function of histamine in the Drosophila nervous system has been linked to photoreceptors and other sensory neuron communication with the nervous system. Histamine is also present in the central nervous system (CNS), although the function of these cells has not been well established. The enzyme that catalyzes the formation of histamine is histidine decarboxylase (Hdc). Using flies containing a gene fusion between the transcriptional control region for the Hdc gene and the Green Fluorescent Protein (eGFP) allowed histamine visualization without the use of a histamine antibody, which is difficult to use in conjunction with other antibodies. These flies (pHdc-eGFP) have previously shown co-localization of histaminergic cells and Hdc gene expression thru GFP. The spatial relationship between histamine and another well characterized neurotransmitter, serotonin, was performed using indirect immunofluorescence with the pHdc-eGFP larva. The results suggest that the locations of histaminergic and serotonergic cells differ from each other, with more serotonergic cells in each segment of the ventral ganglion and brain hemispheres.