Possible interactions between octopamine-immunoreactive (IR) and serotonergic neurons in the CNS of the medicinal leech were investigated. Simultaneous intracellular recordings of serotonin-containing neurons (either the Retzius neuron or cell 21) and the dorsolateral octopamine-IR (DLO) neuron demonstrated that both sets of neurons are coactive at times. Depolarization of either serotonergic c...

1. Systolic pressure in the abdominal artery of the lobster Panulirus japonicus (Von Siebold) was decreased by contraction of the cardioarterial valve located at the posterior exit of the heart. Crustacean neurohormones, octopamine and proctolin, induced rhythmic contractions or contracture of the posterior valve but serotonin did not induce valve contracture. 2. Systolic pressure in the poster...

A comparison between the axon terminals of octopaminergic efferent dorsal or ventral unpaired median neurons in either desert locusts (Schistocerca gregaria) or fruit flies (Drosophila melanogaster) across skeletal muscles reveals many similarities. In both species the octopaminergic axon forms beaded fibers where the boutons or varicosities form type II terminals in contrast to the neuromuscul...

Hepatic encephalopathy (HE) is currently felt to be secondary to a disturbance in the metabolism of cerebral catecholamines with a decline in dopamine and noradrenaline and a rise in the false neurotransmitter octopamine. The aim of this study was to evaluate brain tissue levels of dopamine, noradrenaline, and octopamine in patients with cirrhosis and HE. This study includes 34 patients: 22 wer...

When stung by the parasitoid wasp Ampulex compressa, cockroaches Periplaneta americana enter a hypokinetic state that is characterized by little, if any, spontaneous locomotor activity. In the present study we investigate the effect of an octopamine receptor agonist and an antagonist on the locomotor behavior of stung and control cockroaches. We show that in cockroaches stung by a wasp the octo...

The work presented in this paper is a part of the iCHEM STREP project, which aims at developing a new class of technology for biosynthetic infochemical communication by exploiting recent advances in the understanding of both pheromone biosynthesis pathways and the detection of molecules in the insect nervous system. We present the design and development of a novel surface acoustic wave (SAW) bi...

A subgroup of the large efferent octopaminergic dorsal unpaired median (DUM) neurones of the third thoracic ganglion, the DUM3,4,5 neurones, directly innervates the tendons of certain proprioceptors of the locust hindleg, the so-called strand receptors. The terminals of the DUM neurones occur in regions of the strands that also contain the dendrites of the mechanoreceptive sensory cells. Both s...

1. The release of octopamine from the extensor-tibiae muscle preparation of the locust in response to high K saline and DUMETi stimulation has been demonstrated. This release has been measured using a radioenzyme assay for octopamine. 2. Both forms of stimulated release have been shown to be calcium sensitive. 3. Three potential problems of studying the release of transmitters from neuromuscula...