Sensitivities of antennal olfactory neurons of the malaria mosquito, Anopheles gambiae, to carboxylic acids

Single sensillum recordings on the antennae of female Anopheles gambiae s.s . mosquitoes revealed neurons sensitive to aliphatic carboxylic acids withi n (a) subtype(s) sensilla trichodea. The aliphatic acids, acetic acid, prop ionic acid, butyric acid, iso-butyric acid and iso-valeric acid evoked an i nhibition reaction in one of the cell types recorded from. A different cell type was excited in response; to the former aliphatic acids, but showed a broader range of sensitivity, as acids with a longer carbon chain length, L ike caproic acid, elicited excitations as well. In addition, occasionally 1 -octen-3-ol elicited an excitation reaction. This article focuses on the ca rboxylic acid inhibited cell type and its temporal pattern of response to d ifferent doses of the compounds. Furthermore, in order to compare the stimu latory effectiveness of the compounds on a per molecule basis, corrections were made for differences in volatility by determining the absolute number of molecules in the stimulus puff. (C) 1999 Elsevier Science Ltd. All right s reserved.