Central administration of resistin into the paraventricular nucleus (PVN) produces significant cardiovascular responses

Introduction: Resistin, a complex multimeric structure which is secreted by adipose tissue and circulates in the blood, acts on the hypothalamus to increase sympathetic nerve activity, inhibit appetite and is associated with obesity, insulin resistance and cardiovascular disorders. In this study, we survey the cardiovascular effects of direct injection of resistin into specific cell group of the paraventricular nucleus (PVN) that is known as one of the centers which control the baseline of arterial pressure and heart rate. Methods: Adult male rats were anesthetized with urethane (1.4g/kg intraperitoneally). Arterial pressure (AP) and heart rate (HR) were monitored before and after treatment. Resistin (1, 3 and 5μg/rat), norepinephrine (2.5 nM), muscimol (250ng/rat) and saline as control (vehicle solution, 1μl) were injected into the PVN parvocellular neurons. Results: The results showed that resistin (3 and 5μg/rat) caused a significant increase in AP, HR and high QRS compared to control group and prior to its injection. Injection of norepinephrine into the PVN evoked a significant increase in AP, HR and QRS amplitude, whereas injection of muscimol significantly decreased these parameters. In the control group, saline injection into the PVN had no significant effect on these parameters. Conclusion: It can be concluded that the PVN can be one of the important central areas for actions of resistin which had obvious effects on HR and AP. These results provide a base for future studies to explore the role of resistin in cardiovascular responses in conditions like metabolic syndrome and hypertension.