Glucose is molecule usually studied in relation to metabolism. Except for this traditional view, it is known that under certain conditions glucose can serve as a signal molecule for the circadian system. The circadian system is entrained by relevant synchronizing cues that can be tissue-dependent. Central oscillator is synchronized mainly by light-dark cycle, while peripheral oscillators can be entrained by food intake. Glucose transport in the organism is controlled by insulin dependent and independent mechanism. Therefore, we employed streptozotocin- induced diabetes to elucidate the influence of metabolic changes on glucose transporter ( glut1, glut4 ) 24-h expression profile in peripheral oscillators in tissues, inside (frontal cortex, cerebellum) and outside (heart) the blood-b rain barrier. Diabetes was induced by streptozotocin inje ction. Seventeen days later, sampling was performed during a 24-h cycle. Gene expression was measured using real-time PCR. We observed down- regulation of glut1 and glut4 expression in the heart of diabetic rats. The expression of glut1 and glut4 in brain areas was not down-regulated, however, we ob served trend to phase advance in glut1 expression in the cerebellum. These results may indicate higher glucose levels in diabetic brain, which might influence regulation of clock gene expressi on in different manner in brain compared to periphery., D. Šoltésová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Activation of sublobule IX-b of the cerebellar vermis evokes hypotension, bradycardia and decrease of the phrenic nerve activity in the anesthetized animal. Cardiac performance during the isovolumic phases of systole and relaxation can be evaluated by dP/dt max, Vpm, dP/dt/DP40 and τ, respectively. In the present study, we evaluated the changes on cardiac function evoked by the stimulation of sublobule IX-b. New Zealand white rabbits were anesthetized, paralyzed and artificially ventilated. A posterior craniotomy was made to reveal and stimulate the cerebellar uvula (4 s train; 50 Hz; 1 ms; 20 μA). The femoral artery and veins were cannulated and a Swan-Ganz catheter was advanced in the upper abdominal aorta to control afterload when inflating the balloon. The left ventricle was catheterized with a Millar catheter. Blood pressure, heart rate, left ventricular pressure were monitored. Results showed a significant decrease on sublobule IX-b stimulation of all the indices of systolic function and an increase of τ indicating a decrease in the speed of the relaxation. These data provide the first evidence of the influence of sublobule IX-b on cardiac function. They may contribute to the understanding of the origin the cardiovascular changes that were observed in two patients with vermian and paravermian hemorrhage., I. Rochas, V. Gonçalves, M. J. Bettencourt, L. Silva-Carvalho., and Obsahuje bibliografii a bibliografické odkazy
In the last decade a growing body of data revealed that the cerebellum is involved in the regulation of the affective reactions as well as in forming the associ ation between sensory stimuli and their emotional values. In humans, cerebellar areas around the vermis are activated during mental recall of emotional personal episodes and during learning of a CS-US association. Lesions of the cerebellar vermis may affect retention of a fear memory without altering baseline motor/autonomic responses to the frightening stimuli in both human and animal models. Reversible inactivation of the vermis during the consolidation period impairs retention of fear memory in rodents. Recent findings demonstrate that long-term potentiation (LTP) of synapses in the cerebellar cortex occurs in relati on to associative fear learning similar to previously reported data in the hippocampus and amygdala. Plastic changes affect both excitatory and inhibitory synapses. This concomitant potentiation allows the cerebellar cortical network to detect co incident inputs, presumably conveying sensorial stimuli, with better efficacy by keeping the time resolution of the system unchanged. Collectively, these data suggest that the vermis participates in forming new CS-US association and translate an emotional stat e elaborated elsewhere into autonomic and motor responses., P. Strata, B. Scelfo, B. Sacchetti., and Obsahuje bibliografii a bibliografické odkazy
The name of Jan Evangelista Purkyně and the cerebellum belong inseparably together. He was the first who saw and described the largest nerve cells in the brain, de facto in the cerebellum. The most distinguished researchers of the nervous system then showed him the highest recognition by naming these neurons as Purkinje cells. Through experiments by J. E. Purkyně and his followers properly functionally was attributed to the cerebellum share in precision of motor skills. Despite ongoing and fruitful research, after a relatively long time, especially in the last two decades, scientists had to constantly replenish and re-evaluate the traditional conception of the cerebellum and formulate a new one. It started in the early 1990s, when it was found that cerebellar cortex contains more neurons than the cerebral cortex. Shortly thereafter it was gradually revealed that such enormous numbers of neural cells are not without an impact on brain functions and that the cerebellum, except its traditional role in the motor skills, also participates in higher nervous activity. These new findings were obtained thanks to the introduction of modern methods of examination into the clinical praxis, and experimental procedures using animal models of cerebellar disorders described below., F. Vožeh., and Obsahuje bibliografii