Cellular synthesis and axonal transport of gamma‐aminobutyric acid in a photoreceptor cell of the barnacle.

Abstract

7. These results support the notion that the transmitter substance of the photoreceptor cell of the barnacle is GABA.

Immunocytochemical evidence for the presence of histamine and GABA in photoreceptors of the barnacle (Balanus nubilus)

“…The labeling of the PRs for both histamine and GABA was not unexpected since both compounds may be synthesized by these neurons (Koike & Tsuda, 1980;Stuart & Callaway, 1988;Callaway & Stuart, 19896) and GABA is measurable in the median ocellar nerve (Timpe & Stuart, 1984). In the vertebrate brain, certain neurons of the posterior hypothalamus (but not of other regions) label with antisera directed against both histidine decarboxylase and glutamic acid decarboxylase, indicating that GABA and histamine are present in the same neuron (Takeda et al, 1984).…”

“…The primary candidate for the neurotransmitter used at this synapse has been gamma-aminobutyric acid (GABA) (Koike & Tsuda, 1980;Koike, 1983) but the evidence has not been compelling (Timpe & Stuart, 1984;Callaway & Stuart, Reprint 1989a). A more likely candidate for the PR's transmitter is histamine (Stuart & Callaway, 1988;Callaway & Stuart, 19896), which also appears to be the transmitter of insect PRs (Hardie, 1987;Nassel et al, 1988;Pirovla et al, 1988).…”

“…The ten PRs of the Balanus nubilus visual system converge on a pair of identifiable postsynaptic interneurons, called inverting cells (I-cells) because the synapse is sign-reversing or inhibitory. The primary candidate for the neurotransmitter used at this synapse has been gamma-aminobutyric acid (GABA) (Koike & Tsuda, 1980;Koike, 1983) but the evidence has not been compelling (Timpe & Stuart, 1984; Reprint requests to: Ann E. Stuart, Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7545, USA.…”

“…A more likely candidate for the PR's transmitter is histamine (Stuart & Callaway, 1988;Callaway & Stuart, 19896), which also appears to be the transmitter of insect PRs (Hardie, 1987;Nassel et al, 1988;Pirovla et al, 1988). The photoreceptors are capable of synthesizing both GABA (Koike & Tsuda, 1980) and histamine (Callaway & Stuart, 19896).…”

Comparison of the responses to light and to GABA of cells postsynaptic to barnacle photoreceptors (I-cells)

“…Several indirect lines of evidence have led to the suggestion that GABA is the transmitter released by barnacle photoreceptors (Koike & Tsuda, 1980). Barnacle photoreceptors selectively label with an antibody raised against GABA conjugated to keyhole limpet hemocyanin (Callaway & Edwards, 1987;Callaway et al, 1988.…”