Monika Stengl

Learn More
An antiserum against the crustacean neuropeptide pigment-dispersing hormone stains a small set of neurons in the optic lobes of several hemimetabolous and holometabolous insects. These cells, the primary branches of which in the optic lobe lie in the accessory medulla, fulfill several criteria predicted for neurons of the circadian clock. For example, in(More)
Neurons immunoreactive with antisera against the crustacean peptide β-pigment dispersing hormone fullfill several anatomical criteria proposed for circadian pacemakers in the brain of the cockroach Leucophaea maderae. These include position of somata, projections to the lamina and midbrain and possible coupling pathways between the two pacemakers through(More)
After 2-3 weeks in culture, pupal olfactory receptor neurons from the antennae of male Manduca sexta respond to their species-specific sex pheromone by opening cation channels. These pheromone-dependent cation channels are the only channels previously found in cultured olfactory neurons that promote inward currents at membrane potentials more negative than(More)
Specialized olfactory receptor neurons in insects respond to species-specific sex pheromones with transient rises in inositol trisphosphate and by opening pheromone-dependent cation channels. These channels resemble cation channels which are directly or indirectly Ca2+-dependent. But there appear to be no internal Ca2+ stores in the outer dendrite where the(More)
The biogenic amine octopamine is known to enhance the sensitivity of male moths to their species-specific pheromones in flight-tunnel experiments. This sensitization of pheromone-guided upwind flight is at least partly due to octopamine-dependent increases in the peak nerve impulse frequency of the pheromone response of olfactory receptor neurons. It is not(More)
The presence of an endogenous circadian clock in the brain of an animal was first demonstrated in the cockroach Leucophaea maderae. However, the clock's cellular basis remained elusive until pigment-dispersing hormone-immunoreactive neurons, which express the clock genes period and timeless in Drosophila, were proposed as pacemaker candidates. In several(More)
In moths octopamine improved pheromone-dependent mate search time dependently. In the nocturnal hawkmoth Manduca sexta long-term tip recordings of trichoid sensilla were performed to investigate whether biogenic amines modulate pheromone transduction time dependently. At three Zeitgebertimes octopamine, tyramine and the octopamine antagonist epinastine were(More)
Accumulating evidence suggests that the accessory medulla is the location of the circadian pacemaker in the fruit fly Drosophila melanogaster and the cockroach Leucophaea maderae. gamma-Aminobutyric acid (GABA) and Mas-allatotropin are two putative neurotransmitters, in the accessory medulla in the cockroach Leucophaea maderae. Neurons immunoreactive to the(More)
Adipokinetic hormone (AKH) peptides in insects serve the endocrine control of energy supply. They also produce, however, neuronal, vegetative, and motor effects, suggesting that AKHs orchestrate adaptive behavior by multiple actions. We have cloned, for Periplaneta americana, the AKH receptor to determine its localization and, based on current measurements(More)
Male-specific olfactory receptor neurons, dissociated from developing antennae of the moth Manduca sexta and grown in long-term primary cell culture, can respond to at least one component of the female moth's sex-pheromone blend with the opening of a nonspecific cation channel. This response does not require the coapplication of pheromone-binding protein.