Electrophysiological and neuromuscular relationships in extramural blood vessels

Kreulen, David L.; Keef, Kathleen D.

doi:10.1002/cphy.cp060144

Cited by 3 publications

(2 citation statements)

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“…Mesenteric arteries and veins are both densely innervated 9 and both release ATP along with NA upon stimulation of post‐ganglionic nerve terminals 10,11 . However, sympathetic nerves seem to play significantly different roles in controlling the arterial and venous sides of the splanchnic circulation 21,22 . In the canine mesenteric circulation in particular, the EFS‐evoked overflow of NA in the vein exceeds the overflow of NA in the artery, whereas the ATP overflow is equal in both vascular networks 11 .…”

Section: Discussionmentioning

confidence: 99%

“…10,11 However, sympathetic nerves seem to play significantly different roles in controlling the arterial and venous sides of the splanchnic circulation. 21,22 In the canine mesenteric circulation in particular, the EFS-evoked overflow of NA in the vein exceeds the overflow of NA in the artery, whereas the ATP overflow is equal in both vascular networks. 11 Nerve-evoked overflow of the neurotransmitters is equal to 'released' minus 'removed', so that changes in the concentration of neurotransmitter in the tissue superfusate collected during stimulation of post-ganglionic nerve terminals could be due to either differences in the release of neurotransmitters, in the removal of neurotransmitters or both.…”

Section: Discussionmentioning

confidence: 99%

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Membrane‐bound and releasable nucleotidase activities: Differences in canine mesenteric artery and vein

Bobáľová

Mutafova‐Yambolieva

2003

Clin Exp Pharma Physio

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1. At least two enzymatic activities are proposed to degrade the extracellular ATP: (i) ubiquitously expressed membrane-bound enzymes (ecto-nucleotidases); and (ii) soluble (releasable) nucleotidases that are released during stimulation of sympathetic nerves and break down neuronal ATP. No quantitative data have placed the magnitude of these nucleotidase activities into a physiological perspective of neurovascular control. 2. We studied comparatively the membrane-bound and releasable nucleotidase activities in canine isolated inferior mesenteric arteries and veins using 1,N6-etheno(epsilon)-nucleotides (i.e. epsilon-ATP, epsilon-ADP, epsilon-AMP and epsilon-adenosine) as exogenous substrates. The enzymatic activities were estimated by measuring the disappearance of the epsilon-substrate and appearance of epsilon-products by means of HPLC-fluorescence detection during either stimulation of sympathetic perivascular nerves (releasable activity) or in the absence of nerve stimulation (ecto-nucleotidase activity). 3. Incubation of vascular segments with 50 nmol/L epsilon-ATP for 60 min resulted in a decrease of the epsilon-ATP substrate by 63.5 +/- 4.6 and 91.2 +/- 6.2% in the artery and vein, respectively. In contrast, the decrease of the epsilon-ATP during electrical field stimulation (EFS; 16 Hz, 0.3 msec, 2 min) was 39.8 +/- 4.2% in the artery and 13.1 +/- 7.3% in the vein. Therefore, the mesenteric arteries demonstrate a greater releasable ATPase activity and a weaker ecto-ATPase activity than mesenteric veins. 4. The degradation of epsilon-ADP and epsilon-AMP was similar in both blood vessels under either experimental protocol. The epsilon-adenosine was not significantly degraded in the absence or presence of EFS. 5. These data implicate a differential removal of extracellular ATP as a potential mechanism of serving resistance and capacitance in the splanchnic circulation.

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