ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The release of preloaded [3H]glycine and [3H]taurine in response to a depolarising stimulus (12.5-50 mM KCl) has been studied in the superfused rat retina. High external potassium concentration immediately increased the spontaneous efflux of [3H]glycine, the effect of 50 mM K+ apparently being abolished by omitting calcium from the superfusing medium. In contrast, although high potassium concentrations increased the spontaneous emux of [3H]taurine from the superfused rat retina, this release was not evident until the depolarising stimulus was removed from the superfusing medium. The magnitude of this “late” release of [3H]taurine was dependent on external K+ concentrations, and appeared immediately after cessation of the stimulus irrespective of whether it was applied for 4, 8, or 12 min. Potassium (50 mM)-induced release of taurine appeared partially calcium-dependent, being significantly reduced (p 〈 0.01) but not abolished by replacing calcium with 1 mM EDTA in the superfusate. High-affinity uptake systems for both [3H]glycine and [3H]taurine were demonstrated in the rat retina in vitro (Km values, 1.67 μM and 2.97 μM; Vmax values, 19.3 and 23.1 nmol/g wet weight tissue/h, respectively). The results are discussed with respect to the possible neuro-transmitter roles of both amino acids in the rat retina.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1982.tb07942.x
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