title: Effects of phosphine on the neural regulation of gas exchange in Periplaneta americana.
abstract: Phosphine is used for fumigating stored commodities, however an understanding of the physiological response to phosphine in insects is limited. Here we show how the central pattern generator for ventilation in the central nervous system (CNS) responds to phosphine and influences normal resting gas exchange. Using the American cockroach, Periplaneta americana, that perform discontinuous gas exchange (DGE) at rest, we simultaneously measure ventilatory nervous output from the intact CNS, VCO(2) and water loss from live specimens. Exposure to 800 ppm phosphine at 25 degrees C for 2 h (n=13) during recording did not cause any mortality or obvious sub-lethal effects. Within 60 s of introducing phosphine into the air flow, all animals showed a distinct CNS response accompanied by a burst release of CO(2). The initial ventilatory response to phosphine displaced DGE and was typically followed by low, stable and continuous CO(2) output. CNS output was highest and most orderly under normoxic conditions during DGE. Phosphine caused a series of ventilatory CNS spikes preceding almost complete cessation of CNS output. Minimal CNS output was maintained during the 2 h normoxic recovery period and DGE was not reinstated. VCO(2) was slightly reduced and water loss significantly lower during the recovery period compared with those rates prior to phosphine exposure. A phosphine narcosis effect is rejected based on animals remaining alert at all times during exposure.
authors.affiliation: School of Botany and Zoology, Australian National University, Canberra ACT 0200, Australia. james.woodman@csiro.au
authors.forename: James D
authors.initials: JD
authors.lastname: Woodman
authors.forename: Victoria S
authors.initials: VS
authors.lastname: Haritos
authors.forename: Paul D
authors.initials: PD
authors.lastname: Cooper
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000187:drug effects; D002245:Carbon Dioxide / Q000378:metabolism; D002490:Central Nervous System / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D009068:Movement / Q000187:drug effects; D010526:Periplaneta / Q000187:drug effects* / Q000378:metabolism; D010720:Phosphines / Q000494:pharmacology*; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D015656:Respiratory Mechanics / Q000187:drug effects; D012137:Respiratory System / Q000294:innervation*; D013997:Time Factors; D014870:Water Loss, Insensible / Q000187:drug effects
chemical_list: D007306:Insecticides; D010720:Phosphines; D002245:Carbon Dioxide; C044646:phosphine