Effect of baseline vascular tone on vasomotor responses in cat lip.

Karita, Keishiro; Izumi, Hiroshi

doi:10.1113/jphysiol.1995.sp020550

Cited by 21 publications

(3 citation statements)

References 15 publications

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“…One possible explanation for these contradictory results is that in the rat diaphragm preparation the LDF was used to measure a heterogenous microvascular bed, and the overall change in microvascular response is probably not predictable from the change of Q LDF recorded at a single tissue site. Support for this explanation is provided by findings that the amplitude of a neurogenic vasomotor response can be affected by the magnitude of basal Q LDF in cat lips [23], and that vasomotor responses to pharmacological stimuli vary in different size arterioles in the coronary microcirculation [24][25][26].…”

Section: Discussionmentioning

confidence: 91%

The role of nitric oxide in the spatial heterogeneity of basal microvascular blood flow in the rat diaphragm

et al. 2005

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The effects of N omega-nitro-L: -arginine (L: -NOARG) and N(G)-monomethyl-L: -arginine (L: -NMMA) on the spatial distribution of diaphragmatic microvascular blood flow were assessed in anesthetized, mechanically ventilated rats. Microvascular blood flow was measured after different periods at either a fixed site (Q stat) or 25 different sites (Q scan) using computer-aided laser-Doppler flowmetry (LDF) scanning. The value of Q stat was unaffected after 15-20 min superfusion with any one of the following agents: L: -NOARG (0.1 mM), L: -NMMA (0.1 mM), L: -arg (10 mM). The cumulative frequency histogram of the Q scan value in the control group displayed a non-Gaussian distribution that was not significantly affected after 15 min superfusion with the vehicle of L: -NOARG. Superfusion with either L: -NMMA or L: -NOARG at 0.1 mM for 15 min displaced the histogram of cumulative frequency to the left, with the median value of blood flow decreasing by 10 to 20%. However, skewness and kurtosis of the distribution of basal Q(scan) were unaffected after superfusion of either of the L: -arg analogues. Pretreatment with L: -arg (10 mM), followed by co-administration of L: -arg (10 mM) with L: -NOARG (0.1 mM) only partially prevented L: -NOARG from exerting this inhibitory effect on the distribution of basal Q scan, while pretreatment with L: -arg in the same manner could prevent L: -NMMA from exerting its inhibitory effect. There was a weak but significant linear relationship between the magnitude of basal Q(scan) and normalized changes in basal Q scan after superfusion of either of the L: -arg analogues. In conclusion, a basal NO activity is present in the diaphragmatic microvascular bed of rats. LDF scanning rather may yield more vivid information about the extent of overall tissue perfusion than conventional LDF whenever basal NO activity is involved. Moreover, the parallel flow profiles after NO synthase blockade suggest that the spatial inhomogeneity of basal diaphragmatic microvascular blood flow is not dependent on basal NO formation.

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Section: Discussionmentioning

confidence: 91%

The role of nitric oxide in the spatial heterogeneity of basal microvascular blood flow in the rat diaphragm

et al. 2005

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“…are relaxed), the amplitudes of the vasodilator responses evoked via parasympathetic nerve fibers were weaker (Karita and Izumi, 1995). Our present results indicate that the peripheral vascular tone is important for the degree of parasympathetic vasodilator response.…”

Section: Discussionmentioning

confidence: 42%

“…Isoflurane has been reported to decrease systemic arterial blood pressure by decreasing vascular tone (Bernard et al, 1990(Bernard et al, 1992Conzen et al, 1992;Malan et al, 1995), and the vascular tone affects the magnitude of the vasodilatation (Karita and Izumi, 1995). These findings led us to hypothesize that the peripheral vascular tone plays a role in the suppressive effects of isoflurane on the parasympathetic vasodilatations.…”

Section: Introductionmentioning

confidence: 98%

Effects of Isoflurane on Parasympathetic Vasodilatation in the Rat Submandibular Gland

Mizuta

Mizuta²,

Takahashi³

et al. 2006

J Dent Res

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Volatile anesthetics have been known to suppress parasympathetic reflex vasodilatation in the lower lip and palate. However, in the submandibular gland, little is known about the effects of these anesthetics on the parasympathetic vasodilatation elicited by reflex and direct (i.e., non-reflex) activation of the parasympathetic vasodilator mechanisms. Although both parasympathetic vasodilatations were inhibited by isoflurane in a concentration- and time-dependent manner, the effects of continuous administration of the alpha(1)-adrenoceptor agonist methoxamine were markedly different: The reflex vasodilatation was not affected by methoxamine, while the direct vasodilatation was significantly reduced. Picrotoxin (GABA(A) receptor antagonist) attenuated the inhibitory effect of isoflurane on direct vasodilatation and the systemic arterial blood pressure. These findings suggest that the isoflurane-induced inhibitory effects on direct vasodilatation are produced by a decrease of peripheral vascular tone by GABAergic mechanisms, whereas those on the reflex vasodilatation are produced exclusively by the inhibition of the reflex center.

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Pentylenetetrazole-induced parasympathetic blood flow increase in the lower lip of the cat

Izumi

Takahashi

Karita

1995

European Journal of Pharmacology

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Effect of baseline vascular tone on vasomotor responses in cat lip.

Cited by 21 publications

References 15 publications

The role of nitric oxide in the spatial heterogeneity of basal microvascular blood flow in the rat diaphragm

The role of nitric oxide in the spatial heterogeneity of basal microvascular blood flow in the rat diaphragm

Effects of Isoflurane on Parasympathetic Vasodilatation in the Rat Submandibular Gland

Pentylenetetrazole-induced parasympathetic blood flow increase in the lower lip of the cat

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