Conserved and sexually dimorphic behavioral responses to biogenic amines in decapitated  Drosophila

Abstract

A preparation of decapitated Drosophila melanogaster has been used for direct application of drugs to the nerve cord. Serotonin, dopamine, and octopamine stimulate locomotion and grooming, showing distinguishable effects that often are potentiated by addition of the vertebrate monoamine oxidase-inhibitor hydrazaline. Many of the hydrazaline-induced effects are sexually dimorphic, with males showing greater responses than females. Behaviors similar to those induced by dopamine can be induced by application of the vertebrate dopamine D2-like receptor agonist quinpirole, whose effects are also sexually dimorphic. In contrast, vertebrate D2-like and D1-like dopamine antagonists result in akinesic states, and D1-like agonists selectively stimulate grooming. These data indicate that Drosophila nerve cord amine receptors are coupled to ref lexive behaviors similar to those stimulated by brain dopamine receptors in vertebrates.In both vertebrates and invertebrates, the basic neural oscillators controlling reflex behaviors and locomotion are contained within the spinal cord, or the nerve cord in the case of invertebrates (reviewed in refs. 1-6). Several nonhuman vertebrates show both locomotion and reflex scratching behaviors in response to irritants even after the spinal cord is cut. Similarly, decapitated insects show a basal level of spontaneous grooming as well as a normal grooming response when a sensory bristle is stimulated by gentle mechanical contact (5, 6). Studies in both Drosophila and larger insects show that the grooming response consists of a stereotyped series of leg, wing, and body movements that result in removal of debris from the legs and body of the fly (6-8).Many of these behaviors can be stimulated by application of biogenic amines. Injection of L-DOPA and 5-HTP, the precursors for dopamine͞noradrenaline and serotonin, respectively, can initiate walking motor patterns in spinal cats (9-11) and rabbits (12), although a more recent study shows that adrenergic agents are the most effective (13). Similarly, in partly dissected preparations of moth and locust, addition of dopamine or octopamine to the thoracic ganglia leads to stimulation of flight motor and stepping oscillators (14-16), and in cockroaches, dopamine can stimulate an escape response (17). These applications of exogenous biogenic amines likely mimic the roles of amines and͞or noradrenaline provided to the nerve or spinal cord from the brain by descending projections that are found in both vertebrates and insects (18,19). The invertebrate nerve cord differs from the higher vertebrate spinal cord in that the nerve cord contains aminergic cells bodies (20)(21)(22)(23). Presumably these cell bodies provide localized sources of amines to regions of the nerve cord neuropil that are not accessed by the descending aminergic projections.In vertebrates and invertebrates, dopamine and other amines act through families of G protein-linked seven transmembrane receptors (reviewed in refs. 24-26). Stimulation or inhibition of vertebrate dopamine...

Overexpression of the Drosophila vesicular monoamine transporter increases motor activity and courtship but decreases the behavioral response to cocaine

“…24,25 Similar to cocaine, overexpression of DVMAT increases motor behaviors Pharmacologic studies using cocaine and other aminergic drugs indicate that enhancing aminergic signaling increases both locomotion and grooming in flies, presumably due to an increase in extracellular amine concentrations. 4,6,59 Furthermore, inhibition of DVMAT activity using reserpine decreases locomotor Figure 4 Localization of transgenic DVMAT to synaptic vesicles. Heads isolated from flies homozygous for the elav-GAL4 driver and UAS-DVMAT-A were homogenized and subjected to glycerol gradient fractionation.…”

“…Taken together, our data therefore indicate that an increase in DVMAT-A expression causes an increase in vesicular monoamine release which in turn potentiates motor behaviors, similar to the effects of cocaine and aminergic agonists. 4,6,59 Overexpression of DVMAT alters additional amine-linked behaviors In addition to increased grooming and locomotion, the treatment of flies with cocaine impairs negative geotaxis, the instinctive drive of adult flies to climb upwards against gravity. 6 Similar to this behavioral effect of cocaine, we observe that flies expressing two copies of UAS-DVMAT.III, and two copies of the Ddc-GAL4.II driver show reduced climbing in negative geotaxis assays (Ddc-GAL4;UAS-DVMAT, Figure 7a).…”

“…[1][2][3] In addition, Drosophila exhibit a variety of complex behaviors that are regulated by dopamine (DA) and serotonin (5HT). [4][5][6][7][8][9][10][11][12] Thus, Drosophila provides a powerful system to explore the mechanisms by which aminergic neurotransmission is regulated, and how changes in the presynaptic release of monoamines may influence behavior.…”

Queen pheromone modulates brain dopamine function in worker honey bees

“…HVA (4-hydroxy-3-methoxyphenylethanol) bears a striking structural resemblance to dopamine (see Fig. 1 Right), a biogenic amine that plays a central role in insect behavioral regulation and motor control (11)(12)(13)(14)(15)(16)(17)(18). The presence of this compound within the pheromone blend suggested to us that dopamine function in the brain of recipient bees might be affected by exposure to QMP.…”

Drosophila Vesicular Monoamine Transporter Mutants Can Adapt to Reduced or Eliminated Vesicular Stores of Dopamine and Serotonin

“…In Drosophila melanogaster, dopamine is thought to regulate arousal (van Swinderen et al 2004;Andretic et al 2005;Kume et al 2005), locomotion (Yellman et al 1997;Chang et al 2006), the behavioral effects of cocaine Hirsh 1998, 1999;Torres and Horowitz 1998;Bainton et al 2000), and vitellogenesis (Willard et al 2006). Serotonin regulates visual pathways (Hevers and Hardie 1995;Chen et al 1999), circadian rhythms (Shaw et al 2000;Yuan et al 2006), place memory (Sitaraman et al 2008), and possibly ovarian follicle formation (Willard et al 2006).…”