Illumination Induces Dye Incorporation in Photoreceptor Cells

Abstract

Illumination of fly photoreceptors in the presence of the fluorescent dye Lucifer yellow initiates incorporation of the dye, which stains each cell down to its synaptic terminal. Unilluminated cells do not become stained. Experiments on animals in vivo show that selected cells can be stained without loss of viability. "Induced endocytosis" provides a plausible mechanism underlying this phenomenon.

Mapping of interneurons that contribute to food aversive conditioning in the slug brain.

“…Experiments with peritoneal macrophages have demonstrated that the rate of lysosomal accumulation of LY is markedly e n h a n c e d by phorbol ester stimulation (Swanson et al 1985). Similarly, induced endocytosis of fluorescent dyes could explain reports that sulforhodamine is taken up selectively via neuromuscular junctions upon electrical stimulation (Lichtman et al 1985) and that illuminated photoreceptors are selectively labeled by extracellular LY (Wilcox and Franceschini 1984). Induced endocytosis of LY is postulated as a likely m e c h a n i s m for the selective uptake of LY into the PC interneurons in conditioned slugs, although w e do not yet identify a role of the endocytosis process in the slug's odor learning.…”

“…Fluorescent markers such as LY and sulforhodamine have been used as neural activity markers (Keifer et al 1982;Wilcox and Franceschini 1984). These molecules do not permeate cellular membranes but enter the cell via pinocytosis.…”

“…Expression of the fos protooncogene is useful as an activity marker because that is significantly enhanced by many extracellular stimuli (Curran 1988). Some fluorescent dyes such as sulforhodamine (Keifer et al 1992) and LY (Wilcox and Franceschini 1984) have also been used as activity markers for invertebrate and vertebrate neurons. Keifer et al (1992) described these methods involving the use of fluorescent probes as being better than other approaches in terms of ease of processing and spatial resolution.…”

Applications of Dye‐sensitized Photoreactions in Neurobiology

“…On illumination, however, the dye rapidly penetrates into the cells and stains them down to their synaptic terminals. The mechanism involved in penetration is not known, but may involve light-stimulated endocytosis (Wilcox and Franceschini, 1984;Wunderer et a/., 1989).…”

Imaging Presynaptic Exocytosis in Corticostriatal Slices

“…Fluorophores were then adapted for endocytic labeling of synaptic vesicles, initially using Lucifer yellow in photoreceptors (4). Shortly after Jeff Lichtman and colleagues (5) used rhodamine, fluorescein, and 8-hydroxypyrene (which emit in red, green, and blue wavelengths, respectively) and stimulated multiple nerves innervating a neuromuscular junction to identify which axon terminals were associated with a particular nerve.…”