Development of glucose-6-phosphate, malate, and glutamate dehydrogenase activities in the ventral half of the chick spinal cord in the absence of extrinsic neuronal connections

• Published in: Experimental neurology Vol. 34; no. 2; pp. 342 - 353
• Main Authors: Burt, Alvin M., Narayanan, C.H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.1972
• Subjects: Animals; Chick Embryo; Ganglia; Glucosephosphate Dehydrogenase - metabolism; Glutamate Dehydrogenase - metabolism; Malate Dehydrogenase - metabolism; Neural Pathways; Neurotransmitter Agents - biosynthesis; Spinal Cord - embryology; Spinal Cord - enzymology; Spinal Nerves; Synapses
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/0014-4886(72)90180-X

Microsurgical operations were performed on the neural tube of chick embryos after 50–53 hr of incubation. As a result of the operation, the ventral half of the brachial spinal cord developed in the absence of extrinsic neuronal connections. The levels of activity of glucose-6-phosphate dehydrogenase, malate dehydrogenase, and glutamate dehydrogenase were measured in the ventral half of the brachial spinal cord of both experimental and control embryos 11–21 days of development. The experimental values for both glucose-6-phosphate and malate dehydrogenases were similar to those of control embryos. The level of glutamate dehydrogenase activity was significantly less in the experimental embryos of 19, 20, and 21 days of development. These findings, when considered in the light of other studies, suggest that the differentiation of malate and glucose-6-phosphate dehydrogenase activities is not regulated either by extrinsic neuronal connections, and hence the level of neuronal stimulation, or by the over-all level of motor activity. The reduced levels of glutamate dehydrogenase activity, however, may be a direct reflection of the operative deficit, a reduction in the number of synaptic terminals.