Some Effects of Ether on Bioluminescence in the Lampyrid,Photuris pennsylvanica

Abstract

In normal anesthetic concentrations ether has no direct chemical action on the dehydrogenase system involved in carbohydrate metabolism in mammalian brain, but through humoral effects ether anesthesia in the intact animal has a marked action indirectly on the rate of autoxidation of subsequently excised surviving brain, due presumably to the limiting of available carbohydrate. 1 The present paper demonstrates a striking corollary in the Lampyridae, for while ether has little action directly on the dehydrogenase system having to do with bioluminescence, it does exert various indirect effects in the intact insect which yield again quite unexpected results.

The light-organ of Photuris pennsylvanica generally flashes spontaneously at irregular intermittent intervals. The characteristics of the flash have been studied photoelectrically by Snell 2 and the mechanism of control by Gerretsen, Snell and others, 2 it appears agreed that the flash is under nervous control. Access of adequate oxygen to the light-producing areas, which is a requisite for luminescence, is regulated by supposedly innervated 3 muscular tissue which normally between flashes almost completely occludes the entrance to tracheoles leading to the light-organ. Flashes may be artificially elicited through single shocks or short tetanic electrical stimulation, and the so-called pseudo-flash by rapidly raising the oxygen tension in an environment in which the oxygen concentration is low. Both artificial methods were found to be lacking in uniformity and to have potentialities of irreversibly injuring the flies, in confirmation of Snell's 2 work. Since no regular frequency of flashing can be induced in captured flies, it was obvious that little significant data could be obtained using flashing as a criterion for comparison of treated flies with controls.

Creighton's 3 observation, that injection of minute amounts of epinephrine hydrochloride into the fly results in an action on the occluding musculature of the tracheoles to permit the constant access of oxygen and a resultant constant bright glow of the light-organ, afforded an opportunity of preparing specimens for observation of the direct effects of gaseous agents on the luciferin-luciferase system in situ.