Electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure

Objective: To investigate the electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure.Methods: Guinea pigs model of iron deficiency anemia complicated with chronic heart failure in 10 guinea pigs of the experimental group was made by feeding a low iron diet,pure water and subcutaneous injection of isoproterenol. The control group consisting of 11 guinea pigs was given normal food, normal water and injected with normal saline. The left ventricular outflow tract model specimen was also prepared. The standard microelectrode technique was used to observe electrophysiological changes of autonomic cells in the outflow tract of left ventricular heart failure complicated with iron deficiency anemia in guinea pig model. The indicators of observation were maximal diastolic potential, action potential amplitude, 0 phase maximal depolarization velocity, 4 phase automatic depolarization velocity, repolarization 50% and 90%, and spontaneous discharge frequency.Results: Compared with the control group, 4 phase automatic depolarization velocity,spontaneous discharge frequency and 0 phase maximal depolarization velocity decreased significantly(P < 0.01) and action potential amplitude reduced(P < 0.01) in model group. Moreover, repolarization 50% and 90% increased(P < 0.01).Conclusions: There are electrophysiological abnormalities of the left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with heart failure.

Effect of green flickering light on myopia development and expression of M1 muscarinic acetylcholine receptor in guinea pigs

AIM： To investigate the effects of green flickering light on refractive development and expression of muscarinic acetylcholine receptor（mAChR） M1 in the eyes of guinea pigs.METHODS： Thirty guinea pigs（15-20 days old） were randomly divided into three groups（n=10/group）. Animals in group I were raised in a completely closed carton with green flickering light illumination. Those in group II were kept in the open top closed carton under normal natural light. Guinea pigs were raised in a sight-widen cage under normal natural light in group III. The refractive status and axial length were measured before and after 8 weeks＇ illumination. Moreover, total RNA extracted from retinal, choroidal, and scleral tissues were determined by real-time reverse transcription polymerase chain reaction（RT-PCR）. The expressions of the receptor M1 were also explored in the retina, choroid, and sclera using immunohistochemistry.RESULTS： There was a remarkable reduction in refractive error and increase in axial length after 8-weeks＇ green flickering light stimulation（P〈0.001）. The expression of M1 receptor mRNA in sclera and retina in myopia group were remarkably lower than that in group II and III（P〈0.01）. Significant reduced expression of M1 receptor stimulated by green flickering light in retina and sclera tissues were also observed（P〈0.05）. However, there was no M1 receptor expression in choroid in 3 groups.CONCLUSION： Myopia can be induced by 8 weeks＇ green flickering light exposure in the animal model. M1 receptor may be involved causally or protectively in myopia development.