Circadian rhythms in light-evoked responses of the fly's compound eye, and the effects of neuromodulators 5-HT and the peptide PDF

Abstract

Two sets of wide-field neurons extend neurites into the fly's optic lamina, where monopolar cells receive photoreceptor input. They exhibit immunoreactivity to antibodies raised against either 5-hydroxytryptamine or the crustacean peptide PDH, respectively. Both are proposed whole-field neuromodulators of vision, apparently regulating a circadian rhythm of monopolar cell size. Seeking functional correlates, we have re-examined the electroretinogram for circadian rhythmicity, and for responses to locally injected 5-hydroxytryptamine and peptide. Long-term electroretinogram recordings from Calliphora entrained to a light/dark cycle and then transferred to constant darkness, uncovered a gradual, modest increase during the subjective night in the electroretinogram's ON- and OFF-transients, from the lamina's monopolar cells. Five to twenty nl of 5-hydroxytryptamine (10(-3) mol.1(-1)) injected into the head haemolymph strongly enhanced the electroretinogram transients, an action reversed by 5-hydroxytryptamine antagonists. Injected into the eye, 5-hydroxytryptamine (10(-4) mol.1(-1)) had the opposite effect; the rapid onset there suggests direct action, whilst the opposing effect from haemolymph injection suggests a different receptor site. Pigment-dispersing hormone (2.2 x 10(-5) mol.1(-1)) injected into the haemolymph increased the electroretinogram transients along a biphasic course, with a slow partial recovery; injected into the eye, it lacked effect.

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). Octopamine, which is structurally similar to noradrenaline, is involved in larval locomotion (Saraswati et al 2004;Fox et al 2006) and adult fertility (Monastirioti et al 1996;Cole et al 2005;Middleton et al 2006).…”

“…The adult homozygous dVMAT phenotype includes a blunted response to cocaine and a stronger attraction to light: We next assessed the performance of the dVMAT P1 mutant adults in a series of behaviors previously associated with aminergic signaling (Hevers and Hardie 1995;Hirsh 1998, 1999;Torres and Horowitz 1998;Chen et al 1999;Bainton et al 2000). Because of the conditional survival of homozygous dVMAT P1 null mutants, we were able to test the behavior of flies presumably unable to release serotonin, dopamine, or octopamine from secretory vesicles either during development or in adulthood.…”

“…Vision may also be regulated by monoamines (Hevers and Hardie 1995;Chen et al 1999), and we next tested the performance of the dVMAT mutants using a fast phototaxis assay. We first measured attraction to light in a countercurrent apparatus in which the flies are allowed to choose to run toward light up to five times ( Figure 10B).…”

Advanced High Energy Density Secondary Batteries with Multi‐Electron Reaction Materials

“…In particular, owing to their transfer of three electrons during the reaction process, metal fluoride‐based cathodes meet the target of light weight and multi electron transferring electrodes 130. Because various metals can form compounds with fluoride ions, many kinds of metal fluoride‐based cathodes have been investigated and found to deliver different electrochemical performances in batteries 131. As shown in Table 1 , these metal fluorides universally exhibit higher operating voltages and capacities than those of metal oxides and sulfides.…”

Elementary Motion Detection

“…In addition to an octopamine agonist, other neurotransmitters could be studied as well, such as serotonin, which has already been shown to have an effect on visual motion processing in insects (Donovan , 1986;Chen et al, 1999;Erber et al, 1993). Furthermore, it might be of great interest to examine the effect of octopamine antagonists.…”