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Effect of electrical stimulation and high potassium concentrations on the efflux of [ 14 C] glycine from slices of spinal cord
Author(s) -
HOPKIN JUDY,
NEAL M. J.
Publication year - 1971
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1971.tb07102.x
Subject(s) - glycine , stimulation , potassium , efflux , chemistry , spinal cord , incubation , inhibitory postsynaptic potential , calcium , medicine , endocrinology , biophysics , biochemistry , amino acid , biology , neuroscience , organic chemistry
Summary1 The effects of electrical stimulation and solutions containing a high concentration of potassium on the efflux of [ 14 C] glycine from slices of rat spinal cord have been studied. 2 Slices of cord were incubated with [ 14 C] glycine which rapidly accumulated in the tissue. The slices were then superfused in a small chamber and the radioactivity released from the tissue was measured. After superfusion for 60 min, 98% of the radioactivity remaining in the tissue was present as unchanged glycine. 3 The spontaneous efflux of [ 14 C] glycine consisted of an initial rapid phase followed by a much slower release of [ 14 C] glycine. After superfusion for 60 min, more than 65% of the radioactivity taken up during the incubation period was retained by the tissue. 4 When the slices were depolarized by electrical stimulation or by solutions containing a high concentration of potassium (40 m m ), a striking increase in the efflux of [ 14 C] glycine was produced. This effect was not reduced by the absence of calcium ions in the superfusion medium. 5 Electrical stimulation produced similar increases in the efflux of [ 3 H] GABA and [ 14 C] glutamate from slices of cord but had no significant effects on the efflux of [ 3 H] alanine or [ 14 C] urea. 6 The results are consistent with the suggestion that glycine may be an inhibitory synaptic transmitter substance in the mammalian spinal cord.