Microvascular recruitment in muscle is a determinant of insulin sensitivity. Whether perivascular adipose tissue (PVAT) is involved in disturbed insulin-induced vasoreactivity is unknown, as are the underlying mechanisms. This study investigates whether PVAT regulates insulin-induced vasodilation in muscle, the underlying mechanisms, and how obesity disturbs this vasodilation. Insulin-induced vasoreactivity of resistance arteries was studied with PVAT from C57BL/6 or db/db mice. PVAT weight in muscle was higher in db/db mice compared with C57BL/6 mice. PVAT from C57BL/6 mice uncovered insulin-induced vasodilation; this vasodilation was abrogated with PVAT from db/db mice. Blocking adiponectin abolished the vasodilator effect of insulin in the presence of C57BL/6 PVAT, and adiponectin secretion was lower in db/db PVAT. To investigate this interaction further, resistance arteries of [AMPK[alpha]2.sup.+/+] and [AMPK[alpha]2.sup.-/-] were studied. In [AMPK[alpha]2.sup.-/-] resistance arteries, insulin caused vasoconstriction in the presence of PVAT, and [AMPK[alpha]2.sup.+/+] resistance arteries showed a neutral response. On the other hand, inhibition of the inflammatory kinase Jun N[H.sub.2]-terminal kinase (JNK) in db/db PVAT restored insulin-induced vasodilation in an adiponectin-dependent manner. In conclusion, PVAT controls insulin-induced vasoreactivity in the muscle microcirculation through secretion of adiponectin and subsequent AMPK[alpha]2 signaling. PVAT from obese mice inhibits insulin-induced vasodilation, which can be restored by inhibition of JNK.