Involvement of α2-adrenergic receptor in the regulation of the blood glucose level induced by immobilization stress

Abstract

The blood glucose profiles were characterized after mice were forced into immobilization stress with various exposure durations. The blood glucose level was significantly enhanced by immobilization stress for 30 min or 1 h, respectively. On the other hand, the blood glucose level was not affected in the groups which were forced into immobilization stress for 2 or 4 h. We further examined the effect of yohimbine (an α2-adrenergic receptor antagonist) administered systemically or centrally in the immobilization stress model. Mice were pretreated intraperitoneally (i.p.; from 0.5 to 5 mg/kg), intracerebroventricularly (i.c.v.; from 1 to 10 µg/5 µl), or intrathecally (i.t.; from 1 to 10 µg/5 µl) with yohimbine for 10 min and then, forced into immobilization stress for 30 min. The blood glucose level was measured right after immobilization stress. We found that up-regulation of the blood glucose level induced by immobilization stress was abolished by i.p. pretreatment with yohimbine. And the immobilization stress-induced blood glucose level was not inhibited by i.c.v. or i.t. pretreatment with yohimbine at a lower dose (1 µg/5 µl). However, immobilization stress-induced blood glucose level was significantly inhibited by i.c.v. or i.t. pretreatment with yohimbine at higher doses (5 and 10 µg/5 µl). In addition, the i.p. (5 mg/kg), i.c.v. (10 µg/5 µl), or i.t. (10 µg/5 µl) pretreatment with yohimbine reduced hypothalamic glucose transporter 4 expression. The involvement of α2-adrenergic receptor in regulation of immobilization stress- induced blood glucose level was further confirmed by the i.p, i.c.v, or i.t pretreatment with idazoxan, another specific α2-adrenergic receptor antagonist. Finally, i.p., i.c.v., or i.t. pretreatment with yohimbine attenuated the blood glucose level in D-glucose-fed model. We suggest that α2-adrenergic receptors located at the peripheral, the brain and the spinal cord play important roles in the up-regulation of the blood glucose level in immobilization stress.

Effects of 5,7-dihroxytryptamine administered supraspinally or spinally on the blood glucose level in D-glucose-fed and immobilization stress models

“…As expected we found that restraint stress causes upregulation of blood glucose level; these results are similar to our previous studies . In addition, immobilization stress causes increases in both plasma corticosterone and insulin levels; these findings are in line in part with previous studies (Kang et al 2015;Sharma et al 2015). Furthermore, in the present study, we found that supraspinal or spinal pretreatment with 5,7-DHT causes a downregulation of the blood glucose level in the immobilization stress model.…”

Efficacy and Safety of Different Norepinephrine Regimens for Prevention of Spinal Hypotension in Cesarean Section: A Randomized Trial

“…This phenomenon was found in the study by Ngan Kee et al[ 10 ] as well as in an animal study [ 19 ]. The explanation is as follows: catecholamines regulate blood glucose [ 20 ], sometimes causing hyperglycemia [ 21 ]. Activation of α 1 -adrenoceptors accelerates hepatic glycogenolysis, and α 2 -adrenoceptors are also involved in regulating plasma glucose levels [ 22 – 24 ].…”

The activation of α2-adrenergic receptor in the spinal cord lowers sepsis-induced mortality

“…We have recently observed that clonidine administered spinally increases the blood glucose level [ 24 ]. The upregulation of the blood glucose level induced by spinally administered clonidine is mediated by activating α 2 -adrenergic receptors, since spinal treatment with yohimbine, an α 2 -adrenergic receptor antagonist, completely blocks spinally administered clonidine-induced hyperglycemia [ 24 42 ]. In the present study, we also measured the plasma corticosterone and plasma insulin levels after i.t.…”

“…After brief sonication to shear DNA and reduce viscosity, the concentration of protein was determined with the detergent-compatible protein assay reagent (Bio-Rad Laboratories, USA) using bovine serum albumin as the standard. The western blot analysis was performed according to our previous study [ 38 42 ]. The membranes were then exposed to a Luminescent Image Analyzer (LAS-4000, Fuji Film Co., Japan) for the detection of light emission.…”