Intracellular Responses from the Grasshopper Eye

Abstract

THE compound eye of the grasshopper (Schistocerca vaga vaga) consists of several thousand ommatidia which are arranged in an orderly manner along the radii of the eye. Each ommatidium contains from five to seven cells arranged so that their inner edges meet and form the rhabdome. A capillary microelectrode was introduced into a single ommatidium following a procedure described by Fuortes¹. All experiments were performed on preparations mounted in a perfused oxygenated chamber. Light from an 8 W incandescent filament was attenuated as desired by neutral filters. At zero attenuation, the stimulus intensity was approximately 3 × 10¹⁵ photons (absorbable between 4 and 6 × 10³ Å) cm⁻¹ sec⁻¹. Penetration of ommatidial cells is presumably reflected by a negative potential of 40–70 mV which, in darkness, may remain constant for periods up to 2 h in exceptional cells. This potential decreases during illumination.