Cyclooxygenase-2/PGE2 pathway facilitates pentylenetetrazol-induced seizures.

Cyclooxygenases (COXs) are rate-limiting enzymes in the metabolic pathways in which arachidonic acid is converted to prostaglandins. COX-2 is the isoform induced at injury/inflammation sites and expressed constitutively in a few tissues, such as the central nervous system, and plays a role in neurodegenerative diseases associated with increased excitatory activity. However, the role of COX-2 and its main product, prostaglandin E(2) (PGE(2)), in the convulsive states is not fully established. In this study we showed that the selective COX-2 inhibitor, celecoxib (at the dose of 2mg/kg, but not at the doses of 0.2 or 20mg/kg, p.o.), protects against the seizures induced by pentylenetetrazol (PTZ, 60 mg/kg, i.p.). The role of PGE(2) in the convulsions induced by PTZ was further investigated by administering anti-PGE(2) antibodies (4 microg/2 microl, i.c.v.), and assessing electroencephalographic changes induced by PTZ (PTZ, 60 mg/kg, i.p.). Anti-PGE(2) antibodies attenuated PTZ-induced seizures in rats. In addition, combining PGE(2) (100 ng/2 microl, i.c.v.) with a subconvulsant dose of PTZ (20mg/kg, i.p.) caused seizures, further supporting a role for this prostaglandin in the convulsions induced by PTZ. Finally, we showed that the anticonvulsant action of celecoxib (2mg/kg, p.o.) was reversed by the intracerebroventricular administration of PGE(2) (10 ng/2 microl, i.c.v.). These data constitute strong converging pharmacological evidence supporting a facilitatory role for the COX-2/PGE(2) pathway in the seizures induced by PTZ. However, whether selective COX-2 inhibitors are safer anti-inflammatory drugs for epileptic patients than nonspecific inhibitors remains to be determined.

"Stiff-Man syndrome"associada a poliendocrinopatia autoimune : relato de um caso / Stiff-man syndrome associated with autoimune polyndocrinopathy : report of a case

Os autores relatam o caso de uma paciente de 29 anos, parda, portadora de "stiff-man syndrome" (SMS) associada a poliendocrinopatia do tipo II (moléstia de Basedow-Graves, diabetes mellitus tipo I e tiroidite de Hashimoto). A primeira endocrinopatia foi a doença de Graves que surgiu aos 12 anos e entrou em remissao após um período de tratamento clínico. As manifestaçoes de SMS surgiram há 5 anos, com enrijecimento e espasmos dolorosos dos músculos axiais, e hipertrofia de deltóide e trapézio, tendo desenvolvido diabetes mellitus insulino-dependente (DMI) 2 anos após SMS. Há 1 ano apresentou também hipotiroidismo subclínico (tiroidite de Hashimoto). Foram detectados anticorpos anti-decarboxilase do ácido glutâmico (anti-GAD) no líquor e no soro da paciente, o que confirma o diagnóstico de SMS. Estes autoanticorpos estao voltados contra uma proteína de massa molecular 64 Kd (GAD) e têm sido detectados em 80 por cento dos pacientes com DMI. Pacientes com SMS apresentam alta prevalência desses autoanticorpos e uma grande associaçao com DMI. Na paciente descrita foi possível detectar autoanticorpos contra vários tecidos alvo (tiróide, pâncreas e neurônios GABA-érgicos). Neste relato discute-se os critérios diagnósticos, a fisiopatologia da SMS e os mecanismos imunológicos que levam ao DMI nesta síndrome.