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1. Membrane currents initiated by intense, 20 microseconds flashes (photocurrents) were recorded from isolated salamander rods by combined extracellular suction electrodes and intracellular tight-seal electrodes either in current or voltage clamp mode. The magnitudes (mean +/- 2 S.E.M.) of the maximal photoresponses recorded by the suction and by the(More)
Like retinal rods, cone photoreceptors contain cyclic GMP and light-activated phosphodiesterase. The cGMP phosphodiesterase cascade is thought to mediate phototransduction in rods. Biochemical assays of nucleotide content in cone-dominant retinas, however, have failed to demonstrate light-induced changes in cGMP. Changes in cyclic AMP following light(More)
To test the hypothesis that cyclic GMP is the internal messenger coupling rhodopsin activation to membrane excitation in vertebrate rod photoreceptors, we used a novel technique combining measurement of membrane currents of isolated salamander rods with a suction electrode and the introduction of cyclic GMP through a whole-cell recording patch pipette.(More)
The exenterated orbital contents obtained post mortem from a 47-year-old man who had an eight-month history of treated hyperthyroidism and a two-month history of visual complaints were examined histopathologically, immunohistochemically, and by electron microscopy. All of the extraocular muscles were massively enlarged, due to early diffuse endomysial(More)
We used 18-F-fluoro-2-deoxyglucose positron emission tomography (PET) and computed tomography (CT) to study eight patients with homonymous hemianopias or quadrantanopias due to ischemic lesions of the visual pathways. Four patients with ischemic damage to all or part of the occipital lobe had decreased glucose metabolism in the affected region. Three(More)
The light-modulated current of vertebrate retinal rods flows through a 3',5'-cyclic GMP-dependent conductance located in the outer segment plasma membrane. We report the incorporation into planar bilayers of a conductance derived from vertebrate rod outer segment membranes specifically activated by cGMP but not by cAMP, 5'-GMP, GTP, or 5'-AMP. When the mean(More)