K J Watling

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The effects of vasoactive intestinal peptide (VIP) and several other peptides have been examined on cyclic AMP accumulation in intact pieces and isolated horizontal cells of the teleost (carp) retina. VIP was the most effective peptide examined, inducing a dose-related response, and an approximately fivefold increase in cyclic AMP production when used at a(More)
A specific dopamine-sensitive adenylate cyclase has been identified in homogenates of the teleost (carp) retina. Maximal stimulation by 100 microM-dopamine resulted in a 5--10-fold increase in adenylate cyclase activity with half-maximal stimulation occurring at a concentration of 1 microM. l-Noradrenaline and l-adrenaline were some 10 times less potent(More)
Vasoactive intestinal peptide stimulated the synthesis of adenosine 3',5'-monophosphate in fractions of isolated carp horizontal cells. When applied extracellularly to isolated and cultured horizontal cells, the peptide also induced a slow depolarization (30 to 40 millivolts) accompanied by a decrease in membrane resistance. However, analogs of adenosine(More)
The effects of putative retinal neurotransmitters and several neuropeptides on 3H-dopamine release from isolated perfused carp (Cyprinus carpio) retinas were studied. Of the transmitter candidates tested, only serotonin (5-HT) and the 5-HT agonist tryptamine released 3H-dopamine. However, the release evoked by these agents was calcium (Ca2+) independent and(More)
The ability of dopamine, other proposed retinal transmitters, depolarizing agents, and light to stimulate adenylate cyclase activity in the carp retina has been examined. In both homogenates and pieces of intact tissue, all of the evidence suggests that a dopamine-sensitive adenylate cyclase is the only neurotransmitter activated adenylate cyclase in the(More)
Basal and vasoactive intestinal peptide (VIP)-stimulated accumulations of cyclic AMP were measured in slices of rat cerebral cortex. Neither gamma-aminobutyric acid (GABA) nor the selective GABAB receptor agonist (-)-baclofen stimulated basal cyclic AMP accumulation, whereas VIP caused a large dose-dependent increase in cyclic AMP levels. However, in the(More)
The ability of dopamine, dopamine agonists, other proposed retinal neurotransmitters, depolarizing agents and light to stimulate adenylate cyclase activity in pieces of intact carp retina has been examined. The evidence indicates that a dopamine-sensitive adenylate cyclase is the only neurotransmitter activated adenylate cyclase in the carp retina. That is,(More)
Dopamine-stimulated cyclic AMP accumulation was measured in intact pieces of carp retina following intraocular injections of the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA). This treatment is known to induce a selective destruction of dopaminergic nerve terminals, and in these experiments caused a 94% reduction in retinal dopamine content. However,(More)
At least three distinct receptors for neurotransmitter substances are present on carp horizontal cells. Activation of two of the receptor types, by dopamine and vasoactive intestinal peptide respectively, results in the accumulation of cyclic AMP within the cells. Activation of the third receptor type, by L-glutamate or its analogues, causes a large, 60-80(More)