Elicitation and abrupt termination of behaviorally significant catchlike tension in a primitive insect

✍ Scribed by Hoyle, Graham ;Field, Laurence H.

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 922 KB
• Volume: 14
• Category: Article
• ISSN: 0022-3034
• DOI: 10.1002/neu.480140405

✦ Synopsis

Sustained steady contractural or catchlike tension (CT) occurs in the metathoracic extensor tibiae muscle of the primitive insect the weta (Orthoptera: Stenopelmatidae) during its characteristic leg-extension defense behavior or following leg-position conditioning. Similar action occurs occasionally in semi-intact preparations and is abruptly turned off by a single peripheral inhibitory impulse. These phenomena were reproduced routinely by first infusing saline containing 10-8M (or stronger) octopamine into the muscle for 12 min, and then stimulating the slow excitatory motor neuron SETi with a brief burst. Direct stimulation of the dorsal unpaired median neuron, innervating the extensor tibiae (DUMETi) prior to SETi stimulation, also led to CT. Both octo- pamine and DUMETi markedly enhanced the tension developed in response to a burst of impulses in SETi.