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CB1, a cannabinoid receptor enriched in neuronal tissue, was found in high concentration in retinas of rhesus monkey, mouse, rat, chick, goldfish, and tiger salamander by using a subtype-specific polyclonal antibody. Immunolabeling was detected in the two synaptic layers of the retina, the inner and outer plexiform layers, of all six species examined. In(More)
Bipolar-cell axon terminals receive direct synaptic input from amacrine-cell processes, suggesting a possible pathway for modulation of transmitter release. In retinal slices, bath-applied baclofen, a gamma-aminobutyrate type B (GABAB) receptor agonist, reduced a patch-clamp-recorded L-type calcium channel current in a population of bipolar cells with axon(More)
The transmitter glutamate is thought to be used by all vertebrate photoreceptors to drive the second-order neurons of the retina, horizontal and bipolar neurons. Dopamine, an endogenous retinal neurotransmitter localized to amacrine and interplexiform cells, has previously been shown to enhance glutamate-gated currents in retinal horizontal cells. In the(More)
Amacrine cells of the vertebrate retina comprise multiple neurochemical types. Yet details of their electrophysiological and morphology properties as they relate to neurotransmitter content are limited. This issue of relating light responsiveness, dendritic projection, and neurotransmitter content has been addressed in the retinal slice preparation of the(More)
PURPOSE To determine the presence and distribution of CB1 cannabinoid receptors within the human eye. METHODS A subtype-specific affinity-purified polyclonal antibody to the cannabinoid CB1 receptor was used to determine CB1 localization. Postmortem human eyes were fixed in methacarn and embedded in paraffin. Sagittal sections were mounted on slides and(More)
1. Single-unit extracellular recordings of optic tract fibers were used to study ganglion cell (GC) response properties of the intact cat eye before and after the intravitreal injection of haloperidol or SCH23390, dopamine-specific antagonists. Nearly all of the dopaminergic cells in the cat retina are amacrine cells (ACs); thus the dopamine antagonists are(More)
Whole-cell voltage-gated currents were recorded from bipolar cells in the zebrafish retinal slice. Two physiological populations of bipolar cells were identified. In the first, depolarizing voltage steps elicited a rapidly activating A-current that reached peak amplitude < or = 5 ms of step onset. IA was antagonized by external tetraethylammonium or(More)
To date, two cannabinoid receptors, CB1 and CB2, have been cloned. The CB1 receptor has been found in a variety of tissues, particularly in the brain. CB2 receptor mRNA is mainly expressed in the immune system, though one group has found it in mouse cerebellum. Previous immunostaining studies in our lab demonstrated the presence of CB1 receptors in the(More)
In the present study we measured calcium-dependent, vesicular glutamate release, and calcium-independent, transport-mediated glutamate release patterns in the vertebrate retina to better understand the sources of elevated glutamate in neural tissue under ischemic conditions. A potassium concentration of 40 mM, which mimics the extracellular potassium(More)
The neural circuitry underlying movement detection was inferred from studies of amacrine cells under whole-cell patch clamp in retinal slices. Cells were identified by Lucifer yellow staining. Synaptic inputs were driven by "puffing" transmitter substances at the dendrites of presynaptic cells. Spatial sensitivity profiles for amacrine cells were measured(More)