Locus coeruleus inhibition of vibrissal responses in the trigeminal subnucleus caudalis are reduced in a diabetic mouse model

Diabetic neuropathy is the loss of sensory function beginning distally in lower extremities, which also characterized by pain and substantial morbidity. Furthermore, locus coeruleus (LC) nucleus has been proposed to play an important role descending control through activation α2-noradrenergic (NA) receptors spinal dorsal horn. We studied, on diabetic mice, effect electrical stimulation LC tactile responses caudalis division trigeminal (Sp5C), involved relay orofacial nociceptive information. Diabetes was induced young adult C57BL/6J mice with one intraperitoneal injection streptozotocin (50 mg/kg) daily for 5 days. The animals showed area because they had a decrease withdrawal threshold mechanical vibrissal pad. inhibition Sp5C neurons when applied at 50 100 ms before mice; however, reduced mice. These effects may be due reduction tyrosine hydroxylase positive (TH+) fibers Sp5C, as observed LC-evoked decreased antagonist α2-NA receptors, yohimbine, indicating that it receptors. partially recovered clonidine, non-selective α2-agonist, injected intraperitoneally. findings suggest diabetes, there NA inputs from favor development chronic pain.