Possible role of the internal vertebral venous plexus during exercise in humans

The internal vertebral venous plexus (IVVP) is a thin-walled, valveless venous network that is located inside the vertebral canal, communicating with the cerebral venous sinuses. The objective of this study was to perform a morphometric analysis of the IVVP, dural sac, epidural space and vertebral canal between the L1 and L7 vertebrae with contrast-enhanced computed tomography (CT). Six clinically healthy adult dogs weighing between 12 kg to 28 kg were used in the study. The CT venographic protocol consisted of a manual injection of 880 mgI/kg of contrast agent (587 mgI/kg in a bolus and 293 mgI/mL by continuous infusion). In all CT images, the dimensions of the IVVP, dural sac, and vertebral canal were collected. Dorsal reconstruction CT images showed a continuous rhomboidal morphological pattern for the IVVP. The dural sac was observed as a rounded isodense structure throughout the vertebral canal. The average area of the IVVP ranged from 0.61 to 0.74 mm2 between L1 and L7 vertebrae (6.3–8.9% of the vertebral canal), and the area of the dural sac was between 1.22 and 7.42 mm2 (13.8–72.2% of the vertebral canal). The area of the epidural space between L1 and L7 ranged from 2.85 to 7.78 mm2 (27.8–86.2% of the vertebral canal). This CT venography protocol is a safe method that allows adequate visualization and morphometric evaluation of the IVVP and adjacent structures.

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Regulation of hepatic glucose production during exercise in humans: role of sympathoadrenergic activity

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1993.265.2.e275 ◽

1993 ◽

Vol 265 (2) ◽

pp. E275-E283 ◽

Cited By ~ 23

Author(s):

M. Kjaer ◽

K. Engfred ◽

A. Fernandes ◽

N. H. Secher ◽

H. Galbo

Keyword(s):

Plasma Glucose ◽

Hepatic Glucose Production ◽

Glucose Production ◽

Constant Infusion ◽

Intense Exercise ◽

Nerve Activity ◽

Hepatic Glucose ◽

Sympathoadrenergic Activity ◽

Exercise In Humans

To investigate the role of sympathoadrenergic activity on glucose production (Ra) during exercise, eight healthy males bicycled 20 min at 41 +/- 2 and 74 +/- 4% maximal O2 uptake (VO2max; mean +/- SE) either without (control; Co) or with blockade of sympathetic nerve activity to liver and adrenal medulla by local anesthesia of the celiac ganglion (Bl). Epinephrine (Epi) was in some experiments infused during blockade to match (normal Epi) or exceed (high Epi) Epi levels during Co. A constant infusion of somatostatin and glucagon was given before and during exercise. At rest, insulin was infused at a rate maintaining euglycemia. During intense exercise, insulin infusion was halved to mimic physiological conditions. During exercise, Ra increased in Co from 14.4 +/- 1.0 to 27.8 +/- 3.0 mumol.min-1.kg-1 (41% VO2max) and to 42.3 +/- 5.2 (74% VO2max; P < 0.05). At 41% VO2max, plasma glucose decreased, whereas it increased during 74% VO2max. Ra was not influenced by Bl. In high Epi, Ra rose more markedly compared with control (P < 0.05), and plasma glucose did not fall during mild exercise and increased more during intense exercise (P < 0.05). Free fatty acid and glycerol concentrations were always lower during exercise with than without celiac blockade. We conclude that high physiological concentrations of Epi can enhance Ra in exercising humans, but normally Epi is not a major stimulus. The study suggests that neither sympathetic liver nerve activity is a major stimulus for Ra during exercise. The Ra response is enhanced by a decrease in insulin and probably by unknown stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)

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Idiopathic hypertrophic pachymeningitis with intracranial hypotension and distension of anterior internal vertebral venous plexus are associated with positional headaches but not sufficient in the diagnosis

World Journal of Neuroscience ◽

10.4236/wjns.2013.33020 ◽

2013 ◽

Vol 03 (03) ◽

pp. 154-156

Author(s):

Yongpeng Yu ◽

Changkai Sun ◽

Chen Zhang ◽

Hongqin Zhao ◽

Thian C. Ng

Keyword(s):

Intracranial Hypotension ◽

Hypertrophic Pachymeningitis ◽

Venous Plexus ◽

Internal Vertebral Venous Plexus

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Septic Thrombosis of the Internal Vertebral Venous Plexus : A Rare Cause of Neck Pain

Journal of General and Family Medicine ◽

10.14442/jgfm.16.4_307 ◽

2015 ◽

Vol 16 (4) ◽

pp. 307-308

Author(s):

Yusaku Akashi ◽

Masanari Shiigai ◽

Hiromichi Suzuki

Keyword(s):

Neck Pain ◽

Venous Plexus ◽

Internal Vertebral Venous Plexus ◽

Septic Thrombosis

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Assessing the Role of Muscle Protein Breakdown in Response to Nutrition and Exercise in Humans

Sports Medicine ◽

10.1007/s40279-017-0845-5 ◽

2018 ◽

Vol 48 (S1) ◽

pp. 53-64 ◽

Cited By ~ 32

Author(s):

Kevin D. Tipton ◽

D. Lee Hamilton ◽

Iain J. Gallagher

Keyword(s):

Muscle Protein ◽

Protein Breakdown ◽

Muscle Protein Breakdown ◽

Exercise In Humans

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Opioid antagonism alters blood glucose homeostasis during exercise in humans

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.6.2452 ◽

1994 ◽

Vol 76 (6) ◽

pp. 2452-2460 ◽

Cited By ~ 10

Author(s):

M. S. Hickey ◽

S. W. Trappe ◽

A. C. Blostein ◽

B. A. Edwards ◽

B. Goodpaster ◽

...

Keyword(s):

Serum Insulin ◽

Insulin Response ◽

Serum Glucose ◽

Endogenous Opioid ◽

Hormonal Responses ◽

Blood Glucose Homeostasis ◽

The Difference ◽

Response To Exercise ◽

Exercise In Humans

In an attempt to clarify the role of endogenous opioid peptides in substrate mobilization and hormonal responses to dynamic exercise, eight trained cyclists completed exercise trials at 90% of maximal O2 consumption (VO2max) until exhaustion and at 70% VO2max for 90 min. Trials were conducted after intravenous administration of the opiate antagonist naloxone (NAL, 0.1 mg/kg bolus + 0.1 mg.kg-1.h-1) or volume-matched saline (SAL) at each intensity. Serum glucose was maintained at significantly higher levels at 60 and 90 min of exercise in the 70%-NAL than in the 70%-SAL trial and at all points during exercise and at 30 and 60 min of recovery in the 90%-NAL than in the 90%-SAL trial. The serum insulin response to exercise was not altered by NAL administration at either intensity. Serum C-peptide was approximately 50% higher at 60 and 90 min of exercise in the 70%-NAL than in the 70%-SAL trial but was significantly lower during exercise in the 90%-NAL than in the 90%-SAL trial. The plasma glucagon response to exercise at 70% VO2max was not altered by NAL administration but was significantly elevated in the 90%-NAL vs. the 90%-SAL trial. Plasma epinephrine was 50–150% (approximately 2–3 nM) higher during exercise from 30 to 90 min of exercise in the 70%-NAL than in the 70%-SAL trial and was higher at termination (4.9 +/- 2.1 vs. 2.7 +/- 1.7 nM) in the 90%-NAL than in the 90%-SAL trial, although the difference in the 90% trial was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

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