Dataset Information

Interactions between ?-adrenergic vasodilation and cervical sympathetic nerves are mediated by ?2-adrenoceptors in the rat masseter muscle.

ABSTRACT: Neural and humoral autonomic mechanisms may be important in the maintenance of blood flow in the masseter muscle (MBF). However, their interactions remain unclear. In this study, we examined interactions between neural and humoral regulation of MBF and investigated the mechanisms mediating these interactions in urethane-anesthetized rats. Stimulation of the adrenal nerve (AN) projecting to the adrenal medulla increased MBF, and this increase was mediated by ?-adrenoceptors. Sectioning of the superior cervical sympathetic trunk (CST) significantly inhibited increases in MBF induced by AN stimulation during high activity in the CST, but not during low activity. AN stimulation with clonidine after CST sectioning induced a significant increased in MBF, however phenylephrine had no observable effect. Pretreatment with yohimbine or propranolol significantly inhibited the increase in the MBF. Our results suggest an interaction between ?-adrenergic vasodilation evoked by circulating adrenaline and the cervical sympathetic nerves that is mediated by ?2-adrenoceptors in the masseter muscle.

SUBMITTER: Ishii H

PROVIDER: S-EPMC5910521 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Interactions between β-adrenergic vasodilation and cervical sympathetic nerves are mediated by α<sub>2</sub>-adrenoceptors in the rat masseter muscle.

Ishii Hisayoshi H Sato Toshiya T

The journal of physiological sciences : JPS 20161108 6

Neural and humoral autonomic mechanisms may be important in the maintenance of blood flow in the masseter muscle (MBF). However, their interactions remain unclear. In this study, we examined interactions between neural and humoral regulation of MBF and investigated the mechanisms mediating these interactions in urethane-anesthetized rats. Stimulation of the adrenal nerve (AN) projecting to the adrenal medulla increased MBF, and this increase was mediated by β-adrenoceptors. Sectioning of the sup ...[more]

PMID: 27826897

Similar Datasets

Project description:CD8+ T cells are essential components of the body’s immune reaction against viral infections and tumors, capable of eliminating infected and cancerous cells. However, when the antigen cannot be cleared, T cells enter a state known as exhaustion. Exhausted CD8+ T cells are characterized by expression of multiple inhibitory receptors, like PD-1 and TIM3 and reduced capacity to secrete cytokines, and are commonly found in chronic viral infections, like HIV and HBV, as well as in immunosuppressive tumor microenvironments (TME). Cancer and chronic infection also place considerable stress on tissue architecture and function, and while it is clear that chronic antigen contributes to CD8+ T cell exhaustion, less is known about how stress responses in tissues regulate T cell function. Here we show a previously undescribed link between the stress-associated catecholamines adrenaline and noradrenaline and the development of T cell exhaustion through the β1-adrenergic receptor, ADRB1. We identify that exhausted CD8+ T cells express higher levels of ADRB1, and exposure of ADRB1-expressing T cells to catecholamines suppresses cytokine production and impairs T cell proliferation. Genetic or pharmacological ablation of β-adrenergic signaling via ADRB1 reduces development of T cell exhaustion in a chronic infection model and improves cytotoxic functions in tumor-infiltrating lymphocytes (TILs) when combined with immune checkpoint blockade (ICB) therapy in a melanoma model. Extending these findings to an ICB-resistant tumor model of murine pancreatic cancer, we show that beta-blockers and ICB synergize to enhance and reprogram T cell responses. Given that malignant disease is associated with increased systemic catecholamine levels in patients and therapeutic stress reduction improves survival in cancer patients, our results demonstrate a potential link between systemic stress, tumor innervation and immune responses. Our findings show that β-adrenergic signaling constitutes a novel targetable immune checkpoint in CD8+ T cells to rejuvenate antitumor functions. More broadly, our results support further clinical investigation into the application of beta-blockers, which are clinically safe and widely prescribed, as an immunomodulating agent for cancer immunotherapy.

Project description:BackgroundIncreased nerve activity causes hypertension and kidney disease. Recent studies suggest that renal denervation reduces BP in patients with hypertension. Renal NE release is regulated by prejunctional α2A-adrenoceptors on sympathetic nerves, and α2A-adrenoceptors act as autoreceptors by binding endogenous NE to inhibit its own release. However, the role of α2A-adrenoceptors in the pathogenesis of hypertensive kidney disease is unknown.MethodsWe investigated effects of α2A-adrenoceptor-regulated renal NE release on the development of angiotensin II-dependent hypertension and kidney disease. In uninephrectomized wild-type and α2A-adrenoceptor-knockout mice, we induced hypertensive kidney disease by infusing AngII for 28 days.ResultsUrinary NE excretion and BP did not differ between normotensive α2A-adrenoceptor-knockout mice and wild-type mice at baseline. However, NE excretion increased during AngII treatment, with the knockout mice displaying NE levels that were significantly higher than those of wild-type mice. Accordingly, the α2A-adrenoceptor-knockout mice exhibited a systolic BP increase, which was about 40 mm Hg higher than that found in wild-type mice, and more extensive kidney damage. In isolated kidneys, AngII-enhanced renal nerve stimulation induced NE release and pressor responses to a greater extent in kidneys from α2A-adrenoceptor-knockout mice. Activation of specific sodium transporters accompanied the exaggerated hypertensive BP response in α2A-adrenoceptor-deficient kidneys. These effects depend on renal nerves, as demonstrated by reduced severity of AngII-mediated hypertension and improved kidney function observed in α2A-adrenoceptor-knockout mice after renal denervation.ConclusionsOur findings reveal a protective role of prejunctional inhibitory α2A-adrenoceptors in pathophysiologic conditions with an activated renin-angiotensin system, such as hypertensive kidney disease, and support the concept of sympatholytic therapy as a treatment.

Project description:It is necessary to understand the morphology of the vagus nerve (VN) to design and deliver effective and selective vagus nerve stimulation (VNS) because nerve morphology influences fiber responses to electrical stimulation. Specifically, nerve diameter (and thus, electrode-fiber distance), fascicle diameter, fascicular organization, and perineurium thickness all significantly affect the responses of nerve fibers to electrical signals delivered through a cuff electrode. We quantified the morphology of cervical and subdiaphragmatic VNs in humans, pigs, and rats: effective nerve diameter, number of fascicles, effective fascicle diameters, proportions of endoneurial, perineurial, and epineurial tissues, and perineurium thickness. The human and pig VNs were comparable sizes (?2 mm cervically; ?1.6 mm subdiaphragmatically), while the rat nerves were ten times smaller. The pig nerves had ten times more fascicles-and the fascicles were smaller-than in human nerves (47 vs. 7 fascicles cervically; 38 vs. 5 fascicles subdiaphragmatically). Comparing the cervical to the subdiaphragmatic VNs, the nerves and fascicles were larger at the cervical level for all species and there were more fascicles for pigs. Human morphology generally exhibited greater variability across samples than pigs and rats. A prior study of human somatic nerves indicated that the ratio of perineurium thickness to fascicle diameter was approximately constant across fascicle diameters. However, our data found thicker human and pig VN perineurium than those prior data: the VNs had thicker perineurium for larger fascicles and thicker perineurium normalized by fascicle diameter for smaller fascicles. Understanding these differences in VN morphology between preclinical models and the clinical target, as well as the variability across individuals of a species, is essential for designing suitable cuff electrodes and stimulation parameters and for informing translation of preclinical results to clinical application to advance the therapeutic efficacy of VNS.

Dataset Information

Interactions between ?-adrenergic vasodilation and cervical sympathetic nerves are mediated by ?2-adrenoceptors in the rat masseter muscle.

Publications

Interactions between β-adrenergic vasodilation and cervical sympathetic nerves are mediated by α<sub>2</sub>-adrenoceptors in the rat masseter muscle.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets