Impairment of baroreflex control of heart rate and structural changes of cardiac ganglia in conscious streptozotocin (STZ)-induced diabetic mice

    Authors

    M. Lin; J. Ai; S. W. Harden; C. H. Huang; L. H. Li; R. D. Wurster;Z. X. Cheng

    Comments

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    Abbreviated Journal Title

    Auton. Neurosci-Basic Clin.

    Keywords

    Baroreflex; Nucleus ambiguus; Vagal efferent; Cardiac ganglia; Heart; Diabetes; NUCLEUS AMBIGUUS; AUTONOMIC NEUROPATHY; INDUCED HYPERTENSION; TRANSGENIC; MICE; SENSITIVITY; MELLITUS; OVE26; NEPHROPATHY; MOTONEURONS; DYSFUNCTION; Neurosciences

    Abstract

    Baroreflex control of heart rate (HR) is impaired in human diabetes mellitus and in large experimental models. However, baroreflex impairment in diabetic mouse models and diabetes-induced remodeling of baroreflex circuitry are not well studied. We examined the impairment of baroreflex control of heart rate (HR) and assessed structural remodeling of cardiac ganglia in the streptozotocin (STZ)-induced diabetic mouse model. FVB mice were either injected with vehicle or STZ. Group 1: mice were anesthetized and the femoral artery and vein were catheterized at the 30th day after vehicle or SIT injection. On the second day after surgery, baroreflex-mediated HR responses to sodium nitroprusside (SNP) and phenylephrine (FE)-induced mean arterial blood pressure (MABP) changes were measured in conscious mice. Group 2: Fluoro-Gold was administered (i.p.) to label cardiac ganglia in each mouse at the 25th day after vehicle or STZ injection. After another five days, animals were perfused and cardiac ganglia were examined using confocal microscopy. Compared with control, we found in STZ mice: 1) the HR decreased, but MABP did not. 2) The PE-induced increases of MABP were decreased. 3) Baroreflex bradycardia was attenuated in the rapid MABP ascending phase but the steady-state Delta HR/Delta MABP was not different at all PE doses. 4) SNP-induced MABP decreases were not different. 5) Baroreflex tachycardia was attenuated. 6) The sizes of cardiac ganglia and ganglionic principal neurons were decreased. 7) The ratio of nucleus/cell body of cardiac ganglionic neurons was increased. We conclude that baroreflex control of HR is impaired in conscious SIT mice. In addition, diabetes may induce a significant structural remodeling of cardiac ganglia. Such an anatomical change of cardiac ganglia may provide new information for the understanding of diabetes-induced remodeling of the multiple components within the baroreflex circuitry. (C) 2010 Elsevier B.V. All rights reserved.

    Journal Title

    Autonomic Neuroscience-Basic & Clinical

    Volume

    155

    Issue/Number

    1-2

    Publication Date

    1-1-2010

    Document Type

    Article

    Language

    English

    First Page

    39

    Last Page

    48

    WOS Identifier

    WOS:000279043300008

    ISSN

    1566-0702

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