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THE EFFECT OF CHRONIC DORSAL ROOT SECTION ON THE CONCENTRATION OF FREE AMINO ACIDS IN THE RABBIT SPINAL CORD
Author(s) -
Jones I. M.,
Jordan C. C.,
Morton I. K. M.,
Stagg C. J.,
Webster R. A.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb12223.x
Subject(s) - spinal cord , amino acid , inhibitory postsynaptic potential , excitatory postsynaptic potential , dorsum , cord , neurotransmission , chemistry , anatomy , glutamic acid , reflex , medicine , endocrinology , biology , biochemistry , neuroscience , surgery , receptor
— Amino acids may be involved in primary afferent excitatory neurotransmission in the spinal cord. To test this possibility the effect of chronic dorsal root section on amino acid levels of the rabbit spinal cord has been investigated. Dorsal roots L6‐S2 were sectioned under anaesthesia. Control animals were subjected to similar surgical procedures but the dorsal roots were left intact. Electromyogram recordings taken 6 days after surgery confirmed the absence of sensory input to the lower lumbosacral cord of dorsal root sectioned animals although motor function was retained. In contrast to this control animals exhibited normal reflex activity. The spinal cord was removed from each animal and extracted in trichloracetic acid for subsequent analysts of amino acids on an autoanalyser. Sections of cord were retained for histological determination of neuronal degeneration. Comparison of amino acid levels in dorsal root sectioned and control animals revealed that the only excitatory amino acid to be significantly reduced by dorsal root section wasaspartic acid (–50 percent X although glutamic acid was also reduced (– 30 per cent). Two inhibitory amino acids, cystathionine and GABA, were also significantly depleted (– 50 and ‐ 35 per cent). The possible involvement of these amino acids in spinal cord neurotransmission is discussed.