Excitatory amino acids increase glycogen phosphorylase activity in the rat spinal cord.
Glycogen phosphorylase is present in nervous tissue in an active and inactive form. Using a histochemical technique, an investigation into which putative neurotransmitters have the capacity to modify the activity of the enzyme, has been performed on the rat spinal cord. Intrathecal injections of L-glutamate and L-aspartate elevate glycogen phosphorylase activity in the dorsal horn, while substance P has no effect and only high doses of adenosine triphosphate (ATP) increase the enzyme activity. In addition the N-methyl-D-aspartate receptor antagonist, 5-amino-phosphonovaleric acid was found to block the elevation of glycogen phosphorylase activity in the dorsal horn produced by the peripheral activation of chemo-sensitive primary afferents. Excitatory amino-acid neurotransmitters can therefore, acting via second messengers and protein kinases, modify glycogen metabolism in the spinal cord.
D000818:Animals; D001224:Aspartic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D003655:Decerebrate State; D004789:Enzyme Activation / Q000187:drug effects; D005971:Glutamates / Q000008:administration & dosage / Q000494:pharmacology*; D018698:Glutamic Acid; D007278:Injections, Spinal; D006005:Phosphorylases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface / Q000187:drug effects; D013116:Spinal Cord / Q000201:enzymology*
D005971:Glutamates; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D001224:Aspartic Acid; D018698:Glutamic Acid; D003994:Bucladesine; D000242:Cyclic AMP; D006005:Phosphorylases