INCONGRUENT RESTORATION OF INHIBITORY TRANSMISSION AND GENERAL METABOLIC ACTIVITY DURING REORGANIZATION OF SOMATOSENSORY CORTEX

• Published in: International journal of neuroscience Vol. 115; no. 7; pp. 1003 - 1015
• Main Authors: TREMERE, LIISA A., PINAUD, RAPHAEL
• Format: Journal Article
• Language: English
• Published: London Informa UK Ltd 01.07.2005; Taylor & Francis
• Subjects: Afferent Pathways - enzymology; Amputation; Animals; Biological and medical sciences; Biomarkers - metabolism; cytochrome oxidase; Electron Transport Complex IV - metabolism; Forelimb - innervation; Fundamental and applied biological sciences. Psychology; GABA; GAD; Glutamate Decarboxylase - metabolism; inhibition; Nerve Degeneration - enzymology; Neural Inhibition - physiology; Neurons, Afferent - enzymology; plasticity; Raccoons; reorganization; Sensory Deprivation - physiology; Somatosensory Cortex - cytology; Somatosensory Cortex - enzymology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Toes - innervation; Toes - surgery; Vertebrates: nervous system and sense organs; Human; Enzyme; Central nervous system; Cytochrome-c oxidase; Finger; Lyases; Glutamate decarboxylase; GAD; Encephalon; Somatosensory cortex; Carbon-carbon lyases; cytochrome oxidase; Carboxy-lyases; Somesthetic pathway; Amputation; Plasticity; Neurotransmitter; GABA; Oxidoreductases; Inhibition; reorganization
• ISSN: 0020-7454; 1563-5279; 1543-5245
• DOI: 10.1080/00207450590901503

Activity markers cytochrome oxidase (CO) and glutamic acid decarboxylase (GAD) were analyzed in the primary somatosensory cortex of raccoons that underwent digit amputation. Subjects recovered for 2, 15, and 23 weeks following amputation of the fourth forepaw digit. Histochemistry was used to assess relative activity levels of both enzymes. We found a pronounced decrease in the numbers of CO intense patches in the cortical gyrus that had lost its original sensory input from the fourth digit. This decrease in CO activity was still apparent 15 weeks post-amputation. Conversely, no clear decrease in GAD levels could be identified in connection with the amputation procedure. Our findings present evidence that a significant decrease in metabolic activity results from the loss of the primary afferent sensory drive. The remaining GAD activity suggests that the absence of electrical activity, characteristic of reorganizing cortex, is likely to depend in part on lateral inhibitory cortical connections.