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https://hdl.handle.net/1822/61608
Título: | Diabetes affects the expression of GABA and potassium chloride cotransporter in the spinal cord: a study in streptozotocin diabetic rats |
Autor(es): | Morgado, Carla Pinto-Ribeiro, Filipa Tavares, Isaura |
Palavras-chave: | Animals Blotting, Western Chlorides Diabetes Mellitus, Experimental Diabetic Neuropathies Disease Models, Animal Excitatory Postsynaptic Potentials Glutamate Decarboxylase Immunohistochemistry Male Membrane Potentials Neural Inhibition Posterior Horn Cells Rats Rats, Wistar Symporters Synaptic Transmission Up-Regulation gamma-Aminobutyric Acid Diabetes KCC2 Neuronal hyperactivity Pain modulation Spinal cord Cation chloride cotransporter Sensitization |
Data: | 13-Jun-2008 |
Editora: | Elsevier 1 |
Revista: | Neuroscience Letters |
Resumo(s): | Painful diabetic neuropathy is associated to hyperexcitability and spontaneous hyperactivity of spinal cord neurons. The underlying pathophysiological mechanisms are not clear. Increases in excitatory neurotransmission at the spinal cord, involving glutamate and SP, seem to account for the abnormal neuronal activity, but inhibitory influences were never evaluated. This study aims to analyse the expression of GABA, its synthesizing enzyme glutamic acid decarboxylase (GAD) and the potassium chloride cotransporter (KCC2), in the spinal dorsal horn of streptozotocin (STZ)-induced diabetic rats. Four weeks after saline or STZ (60mg/kg) injection, animals were sacrificed and the spinal segments L2-L3 were removed and immunoreacted for GABA, GAD and KCC2, or processed for western blotting for KCC2. Densitometric quantification was performed in the superficial dorsal horn (laminae I, II and III) of immunoreacted sections and in the immunoblots. STZ rats presented a significant increase of GABA expression in laminae II and III when compared with control animals, while no differences were detected in GAD expression. A significant decrease in KCC2 expression was detected by immunohistochemistry in laminae I and II, which was confirmed by immunoblotting. Increased GABA levels, along with decrease in KCC2 expression, may underlie the abnormal neuronal activity detected in the spinal cord of diabetic rats. Reduction in KCC2 expression was shown to lead to increases in intracellular chloride concentration and, in such condition, GABA binding to GABA(A) receptor induces membrane depolarization, provoking neuronal excitation rather than inhibition. Based on these findings, we propose that a loss of GABA-mediated inhibitory tone at the spinal cord may result in neuronal hyperexcitability and spontaneous hyperactivity during diabetes. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/61608 |
DOI: | 10.1016/j.neulet.2008.04.032 |
ISSN: | 0304-3940 |
e-ISSN: | 1872-7972 |
Arbitragem científica: | yes |
Acesso: | Acesso restrito autor |
Aparece nas coleções: | ICVS - Artigos em revistas internacionais / Papers in international journals |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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morgado2008.pdf Acesso restrito! | 587,76 kB | Adobe PDF | Ver/Abrir |