ABSTRACT
Background: 4-aminopyridine [4-AP] and tetraethylammonium [TEA] are two potassium channel blockers which have shown that have beneficial effects in treating some neurological disorders such as ataxia, Alzheimer and multiple sclerosis. In this study the effect of acute administration of 4-AP and TEA in the treatment of behavioral symptoms of Parkinsonism induced by the toxin 6-hydroxydopamine [6-OHDA] was studied in male rats.
Materials and Methods: 6-OHDA was injected into left medial forebrain bundle [MFB] by stereotaxic surgery using Hamilton syringe. Then, in the third week after surgery, the rats before and after drug application were tested for rotational behavior induced by apomorphine. In the fourth week, Rotarod test was performed in the presence of the blockers for six consecutive days.
Results: 4-AP at doses 200 and 500 MICRO SIGNg/kg had no significant effect, but at dose 1000 MICRO SIGNg/kg led to a significant improvement of behavioral symptoms of Parkinsonism in the rotation test. On the other hand, the drug decreased motor performance and motor learning in the Rotarod test. TEA at dose 1 mg/kg was ineffective, but at dose 2 mg/kg caused a significant decrease, and at dose 5 mg/kg caused a significant increase in the number of rotations of the Parkinsonian rats. TEA had no effect on the motor learning in the Rotarod test.
Conclusion: The results of this study indicate that 4-AP and TEA, in a dose-dependent manner, weaken some symptoms of Parkinsonism, but worsen some other symptoms.
ABSTRACT
Today, due to the modern industrial life of human beings, stress has become prevalent among them and they will suffer from its complications. Exposure to stress during pregnancy can change many babies' normal physiological processes. The separate and combined effects of three common types of prenatal stress were investigated on motor learning of male offspring of rats. In the present study, pregnant NMRI rats were used. Except the control group, the other groups were stressed on the eighth day of gestation for 10 days. The motor learning of 40 male offspring rats were tested using the rotarod performance test 75 days after the experiment. The length of time that each rat could maintain its balance was recorded automatically. The study groups included control, electromagnetic field stress [intensity 1.2 mT, 50 Hz], immobility stress [for 0.5 hour - 2 times/day], social stress [6 rats kept in a small cage], and combined stress [all 3 of the above stresses]. Data were analyzed by using multiple comparisons and Tukey's tests. The motor balance of the combined stress group was lower than the control, at first timing of the first test day [P < 0.05]. In the next few days of the test, the effects of stress on learning of experimental groups were not similar. Combined stress reduced motor learning. Learning fluctuations were higher in electromagnetic field stress group compared to the other groups. The results of our study showed that prenatal combined stress can reduce motor learning of children