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G H Gold

Publications and source records attributed to G H Gold.

22 records · Page 2Linked to original sources
PubMed1979

Photoreceptor coupling in retina of the toad, Bufo marinus. I. Anatomy.

1. Red rod photoreceptors in the toad retina, which are known to be physiologically coupled, were examined for interreceptor contacts. 2. A dense network of large gap junctions was found between the inner segments of red rods, this being the only specialized site of contact that was observed between rods. Each red rod contacts an average of about four neighboring red rods with a junctional area of approximately 0.75 micrometer2. From freeze-fracture micrographs, the density of junctional particles was found to be 5 X 10(3)/micrometer2. 3. The large gap junctions were found only to connect red rods to each other in agreement with physiological data. Only small focal gap junctions were seen between red rods and cones and no junctions were observed between red and green rods. 4. It is concluded that these gap junctions are the site of coupling between the red rods and that the coupling is electrical.

Animals↗
PubMed1979

Photoreceptor coupling in retina of the toad, Bufo marinus. II. Physiology.

1. Intracellular recordings were made from red rods in the isolated toad retina in order to measure the extent of the rod coupling. 2. The network space constant, lambda, was determined from edge-response profile measurements on single cells (lambda = 19 +/- 7 micrometer). 3. The network input resistance was estimated to be between 45 and 100 M omega. 4. Both discrete and continuous resistance networks, which were based on the anatomical observations, were analyzed. For lambda/D greater than 1, a continuous network provides an accurate description of the discrete network (D, cell spacing for a square grid). 5. The network analysis was used to estimate the specific resistance of junction membrane (0.75--1.5 omega.cm2) and the conductance provided by a single junctional channel (2.0--3.9 X 10(-12) mho). 6. The anatomical and physiological results provide strong evidence that the rods are electrically coupled. It is concluded that photoreceptor coupling provides averaging of the voltages in adjacent cells. The consequences of this averaging are discussed.

Animals↗
PubMedDate not supplied

A cyclic nucleotide-gated conductance in olfactory receptor cilia.

Olfactory transduction is thought to be initiated by the binding of odorants to specific receptor proteins in the cilia of olfactory receptor cells. The mechanism by which odorant binding could initiate membrane depolarization is unknown, but the recent discovery of an odorant-stimulated adenylate cyclase in purified olfactory cilia suggests that cyclic AMP may serve as an intracellular messenger for olfactory transduction. If so, then there might be a conductance in the ciliary plasma membrane which is controlled by cAMP. Here we report that excised patches of ciliary plasma membrane, obtained from dissociated receptor cells, contain a conductance which is gated directly by cAMP. This conductance resembles the cyclic GMP-gated conductance that mediates phototransduction in rod and cone outer segments, but differs in that it is activated by both cAMP and cGMP. Our data provide a mechanistic basis by which an odorant-stimulated increase in cyclic nucleotide concentration could lead to an increase in membrane conductance and therefore, to membrane depolarization. These data suggest a remarkable similarity between the mechanisms of olfactory and visual transduction and indicate considerable conservation of sensory transduction mechanisms.

Animals↗