A novel kainate receptor in the insect nervous system.

The pharmacology of excitatory amino acid receptors on an identified neurone in the insect central nervous system was investigated using single electrode recording techniques. Application of kainate, domoate and quisqualate elicited large, slow depolarizations with a rise time of approximately 4 min and recovery time of 23 min. Concentration-response curves were constructed giving an order of potency, domoate greater than quisqualate greater than kainate, and fitted curves demonstrated quisqualate to be a possible partial agonist, compared to domoate and kainate. Agonist responses were insensitive to the antagonists CNQX and picrotoxin and the vertebrate receptor-subtype selective agonists AMPA and trans-ACPD did not elicit any response, suggesting a novel type of excitatory amino acid receptor present on neurones in the insect central nervous system.