Chemicals in Laboratory Room Air Stimulate Olfactory Neurons of Female Bombyx mori

Abstract

Laboratory air contained odorants that elicited electrophysiological responses in female Bombyx mori antennae. Air entrainments on charcoal filters, extracted with CS(2) and subsequently with acetone, were analyzed by coupled gas chromatography (GC)-electroantennogram (EAG) as well as by GC-mass spectrometry. The CS(2) extract contained 12 EAG-active peaks from which benzaldehyde, octanal, limonene, 1,8-cineol, methyl benzoate, nonanal, decanal and geranyl acetone were identified. In the acetone extract we identified eight EAG-active peaks as phenol, nonanal, 2-ethylhexanoic acid, octanoic acid, benzoic acid, nonanoic acid, decanoic acid and dimethyl phthalate. The concentrations of benzoic acid and benzaldehyde present in laboratory air were determined. The origin of the substances and importance of such odorants in laboratory air for the interpretation of physiological experiments on the olfactory system is discussed.

The electroolfactogram: A review of its history and uses

“…The EAG has been used to evaluate the response to pheromones across related species of moths (Priesner, 1969). Ziesmann et al (2000) used the EAG to assess odorous contaminants in laboratory room air. It has been used to assess the rate of development of odorant sensitivity in moths (Schweitzer et al, 1976).…”

Inhibitory and Excitatory Effects of Iodobenzene on the Antennal Benzoic Acid Receptor Cells of the Female Silk Moth Bombyx mori L.

“…In moths, these cells are found in long-hair sensilla called sensilla trichodea. Examples of inhibitors for odor specialists are geraniol for pheromone receptors in the moth Antheraea polyphemus (Schneider et al, 1964), (±)-linalool for the bombykol receptor cell of the male of the silk moth Bombyx mori (Kaissling et al, 1989) or aniline for the receptor cell for benzoic acid (BA) of the female of B. mori (Priesner, 1979;Kaissling, 1987;Heinbockel and Kaissling, 1990;Ziesmann et al, 2000;de Brito Sanchez, 1996). Interestingly, (±)-linalool, the above-mentioned inhibitor of a specialist pheromone receptor cell in the male of B. mori, strongly excites a cell occurring together with the BA receptor cell in the same sensillum of the female (Heinbockel and Kaissling 1996).…”

Benzoic acid, a stimulant of odorant receptors of Bombyx mori, is rapidly metabolized to N-benzoylserine on the antennae

“…The time course of the nerve impulse response of the benzoic acid cell varied between a tonic pattern, with a slow decrease of impulse activity after the end of stimulation, and a phasic-tonic pattern with a more rapid decrease of impulse activity (Heinbockel & Kaissling 1995). Since large numbers of receptor cells on the female antennae are highly sensitive, and are tuned specifically to the non-pheromone odorant benzoic acid (De Brito Sanchez 1996Ziesmann et al 2000), we decided to study the mode of the odorant deactivation by application of labelled benzoic acid. Following exposure of the antenna to vapours of [ 2 H 5 ]-benzoic acid, and mass spectrometry of the isolated metabolites, we obtained first evidence for a novel type of odorant-deactivation by conjugation with the antennal amino acid serine.…”