+ Site Statistics
+ Resolve Accession
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
Submit PDF Full TextSubmit PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Sympathetic influence on cardiovascular responses to sustained head-up tilt in humans

, : Sympathetic influence on cardiovascular responses to sustained head-up tilt in humans. Acta Physiologica Scandinavica 155(4): 435-444

Sympathetic beta-adrenergic influences on cardiovascular responses to 50 degrees head-up tilt were evaluated with metoprolol (beta 1-blockade; 0.29 mg kg-1) and propranolol (beta 1 and beta 2-blockade; 0.28 mg kg-1) in eight males. A normotensive-tachycardic phase was followed by a hypotensive-bradycardic episode associated with presyncopal symptoms after 23 +/- 3 min (control, mean +/- SE). Head-up tilt made thoracic electrical impedance (3.0 +/- 1.0 omega), mean arterial pressure (MAP, 86 +/- 4-93 +/- 4 mmHg), heart rate (HR, 63 +/- 3-99 +/- 10 beats min-1) and total peripheral resistance (TPR, 15 +/- 1-28 +/- 4 mmHg min L-1) increase, while central venous oxygen saturation (74 +/- 2-58 +/- 4%), cardiac output (5.7 +/- 0.1-3.1 +/- 0.3 L min-1), stroke volume (95 +/- 6-41 +/- 5 mL) and pulse pressure (55 +/- 4-49 +/- 4 mmHg) decreased (P < 0.05). Central venous pressure decreased during head-up tilt (7 +/- 2-0 +/- 1 mmHg), but it remained stable during the sustained tilt. At the appearance of presyncopal symptoms MAP (49 +/- 3 mmHg), HR (66 +/- 4 beats min-1) and TPR (15 +/- 3 mmHg min L-1) decreased (P < 0.05). Neither metoprolol or propranolol changed tilt tolerance or cardiovascular variables, except for HR that remained at 57 +/- 2 (metoprolol) and 55 +/- 3 beats min-1 (propranolol), and MAP that remained at 87 +/- 5 mmHg during the first phase with metoprolol. In conclusion, sympathetic activation was crucial for the heart rate elevation during normotensive head-up tilt, but not for tilt tolerance or for the associated hypotension and bradycardia.

Order PDF Full Text


Click here to order any other PDF Full Text

Accession: 009499888

PMID: 8719263

DOI: 10.1111/j.1748-1716.1995.tb09993.x

PDF Full Text: Sympathetic influence on cardiovascular responses to sustained head-up tilt in humans

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Other references

Dietz W.H.; Wolfe R.R., 1981: Hypo caloric diets in obese adolescents effects of dietary glucose or fat on the interrelationships of protein and glucose metabolism. American Journal of Clinical Nutrition 34(4): 623

Khan, S.; Koerner, M.M.; Pae, W.; Stephenson, E.R.; Weber, H.; Brehm, C.; El-Banayosy, A., 2014: Successful percutaneous transcatheter aortic valve replacement in multi-organ failure due to aortic bioprosthesis regurgitation in a patient with continuous-flow LVAD. Journal of Heart and Lung Transplantation 32(6): 659-663

Khurana, J.; Chugh, A.; Khurana, P., 2002: Regeneration from mature and immature embryos and transient gene expression via Agrobacterium-mediated transformation in emmer wheat (Triticum dicoccum Schuble). The present study establishes a regeneration protocol and optimizes conditions for Agrobacterium-mediated transformation of the tetraploid emmer wheat, Triticum dicoccum. Regeneration from mature and immature embryos was accomplished as a two-step...

Heilmann, A.; Teuscher, N.; Kiesow, A.; Janasek, D.; Spohn, U., 2004: Nanoporous aluminum oxide as a novel support material for enzyme biosensors. To construct novel amperometric sensors for the detection of hydrogen peroxide and pyruvate, peroxidase and pyruvate oxidase were immobilized in self-supporting nanoporous alumina membranes those made by anodic oxidation. Pyruvate oxidase and othe...

Dunlop, E., 1968: Suicide-a cultural phenomenon. Canadian Family Physician Medecin de Famille Canadien 14(11): 68-75

Shaw, FC., 1974: Simpson Group (Middle Ordovician) trilobites of Oklahoma. Journal Paleont, 485 1-54,1-12 Suppl., pt. 2 of 2

Mardon, J.; Nesterova, A.P.; Traugott, J.; Saunders, S.M.; Bonadonna, F., 2010: Insight of scent: experimental evidence of olfactory capabilities in the wandering albatross (Diomedea exulans). Wandering albatrosses routinely forage over thousands of kilometres of open ocean, but the sensory mechanisms used in the food search itself have not been completely elucidated. Recent telemetry studies show that some spatial behaviours of the spe...

Biasi, F.; Vizio, B.; Mascia, C.; Gaia, E.; Zarkovic, N.; Chiarpotto, E.; Leonarduzzi, G.; Poli, G., 2006: C-Jun N-terminal kinase upregulation as a key event in the proapoptotic interaction between transforming growth factor-beta 1 and 4-hydroxynonenal in colon mucosa. Cells of colonic mucosa are sensitive to the Smad-mediated growth-inhibitory effect of transforming growth factor-beta 1 (TGF-beta 1). Another important cell growth inhibitor is the polyunsaturated lipid peroxidation end product, 4-hydroxynonenal...

van den Heuvel, S.J.; van Laar, T.; Kast, W.M.; Melief, C.J.; Zantema, A.; van der Eb, A.J., 1990: Association between the cellular p53 and the adenovirus 5 E1B-55kd proteins reduces the oncogenicity of Ad-transformed cells. The association of the cellular p53 protein with the E1B-55kd protein of adenovirus 5 (Ad5) is thought to result in inactivation of the p53 recessive oncogene product. Here we show that Ad5 E1-transformed 3Y1 rat cells which express low levels of...

Bointner, K.; Duftschmid, G., 2009: HL7 template model and EN/ISO 13606 archetype object model - a comparison. HL7 Templates and EN/ISO 13606 Archetypes are essential components for a semantically interoperable exchange of electronic health record (EHR) data. In this article the underlying models from which Templates and Archetypes are instantiated, namely...