Improvement of Obesity by Activation of I₁-Imidazoline Receptors in High Fat Diet-fed Mice

Abstract

Imidazoline I₁-receptor (I₁R) is known to regulate the blood pressure, and rilmenidine, as the agonist, is used to treat hypertension in clinics. However, the role of I₁R in obesity is still unclear. In the present study, we investigated the changes of obesity by activation of I₁R in high fat diet (HFD)-fed mice. Chronic administration of rilmenidine into HFD-fed mice for 8 weeks significantly reduced body weight, which was reversed by efaroxan at the dose sufficient to block I₁R. Also, rilmenidine significantly decreased the energy intake of HFD-fed mice. This reduction of energy intake was abolished by efaroxan at the same dosing for blockade of I₁R. However, hypothalamic I₁R protein expression in HFD-fed mice was markedly lower than that in normal chow-fed mice. In addition, epididymal white adipose tissue (eWAT) cell size in HFD-fed mice was decreased by rilmenidine via the activation of I₁R. Moreover, effect of rilmenidine on appetite disappeared in db/db mice. Taken together, we suggest that rilmenidine can improve obesity in HFD-fed mice through an activation of I₁R to ameliorate energy intake and eWAT accumulation.

Key words

energy intake - high fat diet-induced mice - hyperphagia - imidazoline I₁-receptors

• References

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