Octopamine partially restores walking in hypokinetic cockroaches stung by the parasitoid wasp Ampulex compressa.
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 octopamine receptor agonist chlordimeform induces a significant increase in spontaneous walking. In good agreement, in control individuals an octopamine receptor antagonist significantly reduces walking activity. Adipokinetic hormone I (AKH-I) promotes spontaneous walking in controls but does not do so in stung individuals, which suggests that the venom effect is most probably not mediated by AKH-I. Dopamine receptor agonists or antagonists had no significant effect on the spontaneous walking of stung or control cockroaches, respectively. The effect of the octopamine receptor agonist was maximal when injected into the brain, suggesting that the wasp venom interferes with octopaminergic modulation of walking initiation in central structures of the cockroach brain.
Department of Life Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Lior Ann
LA
Rosenberg
Jose Gustavo
JG
Glusman
Frederic
F
Libersat
D000818:Animals; D001921:Brain / Q000187:drug effects; D002742:Chlorphenamidine / Q000494:pharmacology; D003058:Cockroaches / Q000187:drug effects / Q000469:parasitology* / Q000502:physiology*; D003984:Dibenzazepines / Q000494:pharmacology; D017952:Ganglia, Invertebrate / Q000187:drug effects; D006458:Hemolymph / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D007267:Injections; D007299:Insect Bites and Stings; D007301:Insect Hormones / Q000494:pharmacology; D008297:Male; D009655:Octopamine / Q000378:metabolism*; D010271:Parasites / Q000502:physiology*; D017982:Receptors, Biogenic Amine / Q000819:agonists / Q000037:antagonists & inhibitors; D011954:Receptors, Dopamine / Q000378:metabolism; D013997:Time Factors; D016138:Walking / Q000502:physiology*; D014863:Wasps / Q000502:physiology*
D003984:Dibenzazepines; D007093:Imidazoles; D007301:Insect Hormones; D017982:Receptors, Biogenic Amine; D011954:Receptors, Dopamine; C027604:norsynephrine receptor; D009655:Octopamine; D002742:Chlorphenamidine; C053090:epinastine