Avaliação da reatividade coronariana do coração isolado de ratos submetidos ao modelo de indução de epilepsia pela pilocarpina
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2016-09-19
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Universidade Federal de Goiás
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Epilepsy is the most common chronic neurological disease in the world, characterized by
paroxysmal, excessive and synchronous discharges of a neuronal population that leads to
spontaneous and recurrent seizures. Sudden unexpected death in epilepsy (SUDEP) is
responsible for 7.5% to 17% of deaths in epilepsy. Although the pathophysiological
mechanisms are unknown, one possible explanation is that they are of cardiogenic origin.
Some studies relate cardiac abnormalities with seizures, and these may be responsible for
Suped, and as yet has no works that have investigated the control of coronary flow of patients
or in experimental models of epilepsy, and as coronary heart disease listed as one of the main
causes of sudden death in the world population, assess coronary flow in experimental epilepsy
model becomes important for the understanding of SUDEP. So this study aims to evaluate the
coronary reactivity, ventricular function and cardiac tissue of rats submitted to the pilocarpine
model of epilepsy. The animals were separated into two groups: control (n = 8) and epilepsy
(n = 8). It was administered 350 mg/kg of pilocarpine (i.p) preceded by 1mg/kg
methylscopolamine (s.c) in both groups, animals that entered in status epilepticus received
diazepam 10 mg/kg (i.p) after 3 hours to block it. After that, the animals were placed in a
room for video monitoring (24 h/day) until complete two months of epilepsy (epilepsy group).
Rats that received pilocarpine and did not develop status epilepticus comprised the control
group, being housed in the same animal environment that epilepsy group. At two months of
chronic epilepsy rats were sacrificed and the heart dissected to the Langendorff preparation
(constant flow), after a 35 minutes of stabilization in a Krebs - Ringer solution bradykinin (BK)
was administered (10ˉ⁸, 10ˉ⁷, 10ˉ⁶ and 10ˉ⁵M) in bolus and after of washout was treated
with sodium nitroprusside in different concentrations (10ˉ⁶, 10ˉ⁵, 10ˉ⁴ and 10ˉ³M) also
bolus. They were found in animals with epilepsy a significant reduction in coronary relaxation
by BK infusion at a concentration 10ˉ⁵M. It was observed that rats with epilepsy have
increased perivascular collagen, larger cardiomyocytes, and more coronary arteries, with no
change of nitric oxide synthase endoletial (eNOS), superoxide dismutase (SOD) and catalase
expression. Thus, our results show reduction of coronary relaxation induced by bradykinin
which leads us to believe in loss of endothelial function of these animals, since, we did not
observe differences in relaxation induced by sodium nitroprusside, despite the perivascular
fibrosis of epileptic rats.
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VITORINO, P. R. Avaliação da reatividade coronariana do coração isolado de ratos submetidos ao modelo de indução de epilepsia pela pilocarpina. 2016. 57 f. Dissertação (Mestrado em Ciências Fisiológicas) - Universidade Federal de Goiás, Goiânia, 2016.