Postnatal Ontogenetic Development of Neurogenic and Myogenic Control in the Rat Portal Vein

Ljung, Bengt; Stage, Dorothy

doi:10.1111/j.1748-1716.1975.tb05867.x

Cited by 37 publications

(13 citation statements)

References 19 publications

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“…Alternatively, it is reasonable to assume that excitatory neuromuscular transmission is not completed and/or effective innervations are not well-established in newly hatched chickens. This assumption is consistent with results of a study by Ljung and Stage (1975), showing that responsiveness of vascular smooth muscle to exogenous noradrenaline is established before the development of sympathetic innervation.…”

Section: Discussionsupporting

confidence: 87%

“…At birth, no or little nerve terminal network is observed, whereas a plexus of nerve fibers and varicosities appear after the first postnatal week in several blood vessels of various mammalian species (Luff, 1999). In accordance with this, perivascular nerve stimulation induced contractile responses after the first postnatal week in rat portal veins (Ljung and Stage, 1975) and in rat irideal arterioles (Sandow and Hill, 1999).…”

Section: Introductionmentioning

confidence: 67%

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Postnatal development of excitatory innervations in longitudinal smooth muscle of the chicken anterior mesenteric artery

et al. 2011

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 67%

Postnatal development of excitatory innervations in longitudinal smooth muscle of the chicken anterior mesenteric artery

et al. 2011

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“…8 This study concurs with the predominance of the T current in these WKY cells and shows that in similar vascular cells from genetically matched SHR, the L current is three times greater than the T current. Since all cells studied were obtained from neonatal rats (1-3 days old) and blood vessels are not effectively innervated until at least 1-3 weeks of age, 20 it is unlikely that a neurogenic influence in the blood vessel wall or exposure of the vascular muscle cell to norepinephrine accounted for the greater proportion of L channel current in SHR cells. It is also unlikely that a structural alteration of the blood vessel wall secondary to a greater distending pressure was involved.…”

Section: Discussionmentioning

confidence: 99%

Calcium currents are altered in the vascular muscle cell membrane of spontaneously hypertensive rats.

Rusch

Hermsmeyer

1988

Circulation Research

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Calcium currents were recorded during whole-cell voltage damp in cultured azygos venous muscle cells from 1-3-day-old normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Different holding potentials were used to separate total cell current into its transient (T) and sustained or long-lasting (L) components. In recordings from 30 WKY and 30 SHR vascular cells, total cell calcium current was the same between cells from normotensive (167±20 pA) and hypertensive (139±15 pA) rats. However, the relative proportion of T and L calcium currents was different between WKY and SHR cells. In WKY cells, the peak amplitude of the L current was less than that of the T current (42±30% of total current), whereas in SHR cells, the L current was greater (62±3% of total current). Calcium currents in vascular muscle cells from SHR were activated and inactivated at more positive potentials than in cells from WKY. This study directly compares transmembrane calcium current in isolated cells from WKY and SHR blood vessels and shows that the proportions of T and L calcium channels activated by depolarization are altered in this genetic model of hypertension. ). Cellular mechanisms of calcium metabolism reported to be associated with hypertension in the spontaneously hypertensive rat (SHR) include changes in intracellular release and reuptake of calcium and alterations in sarcolemmal transport of and permeability to the ion. 2 -6 The recent introduction of the tight-seal patchclamp technique 7 for the measurement of transmembrane calcium currents in vascular muscle cells 8 -13 enables the implementation of a powerful tool to directly compare the properties of voltage-dependent calcium channels in cells from normotensive and hypertensive animals. In the experiments described here, we used the whole-cell voltage-clamp technique 7 to measure calcium currents and compared the voltagedependent calcium channels in cultured vascular mus-

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“…Thus, the design appears to associate a larger cell at a steeper angle with denser innervation. The densely innervated portal vein (Ljung and Stage, 1975), with little paracellular matrix within the muscle layers, has the smallest smooth muscle cells. In this case, the size may be related to the very low pressure within that vessel.…”

Section: Discussionmentioning

confidence: 99%

The dimensional characteristics of smooth muscle in rat blood vessels. A computer-assisted analysis.

Todd¹,

Laye²,

Osborne³

1983

Circulation Research

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SUMMARY. This investigation was undertaken to provide precise information about the dimensional characteristics of vascular smooth muscle cells as related to their paracellular matrix. The representative types of vessels were fixed at the mean blood pressures of adult male Wistar rats. The shapes, positions of the nucleus, linear dimensions, volumes, and orientation within the vessel wall were determined by a computer-assisted reconstruction of the cells from serial sections. Wall-to-lumen and cellular-to-paracellular ratios also were assessed. The smooth muscle cells were elongate, but whereas some are spindle shaped, most are not, and may be shaped like flattened triangles, paddles, boomerangs, or hourglasses, and in addition, any one of these shapes may be forked. The nucleus tended to be in the largest part of the cell, wherever that region occurred. Thus, the majority of the nuclei (61%) were not centrally located, but overlapped the middle and end thirds of the elongate cells. Of the three arteries investigated, the muscular type tail artery had cells with volumes two to three times larger (P < 0.01) than cells in a musculoelastic (femoral) or elastic (mesenteric) artery, and six times larger (P < 0.01) than those of the portal vein. Therefore, the smooth muscle cells of the vein were significantly smaller than those in any artery (P < 0.01). The smooth muscle cells were aligned at a steeper angle in the vessel wall (15°± 2°) of the muscular artery than in those with more elastic tissue (9° ± 2°), with a higher percentage of circumferential cells in the latter. The wall-to-lumen ratios decreased as the relative amount of paracellular matrix, particularly elastic tissue, increased in the three arteries. Therefore, irregularly shaped cells, with the nucleus in the thickest region, and having characteristic cell volumes depending on the type of vessel, form the vascular smooth muscle tissue. These factors are relevant if stereology, or measuring from two dimensions, is used to estimate size characteristics in cardiovascular disease such as hypertension. In addition, the optimum angle at which vascular strips are cut would vary, for example, when used in testing pharmacological agents. (Circ Res 53: [319][320][321][322][323][324][325][326][327][328][329][330][331] 1983) SMOOTH muscle tissue is believed to consist of spindle-shaped cells with a central nucleus oriented along the long axis of the cell (see reviews by Rhodin, 1980;Gabella, 1981). The orientation of smooth muscle cells in blood vessels is assumed to be spiral or helical, although the results of experiments are more consistent with a circular orientation in some vessels. Knowledge of the shape and orientation of smooth muscle cells in blood vessels is important in interpreting normal and pathological pressures in blood vessels, as well as tension in strip preparations of vessel wall.We have developed techniques to provide definitive information about the size, shape, and orientation of smooth muscle cells in blood vessels. Serial sections of ves...

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Postnatal Ontogenetic Development of Neurogenic and Myogenic Control in the Rat Portal Vein

Cited by 37 publications

References 19 publications

Postnatal development of excitatory innervations in longitudinal smooth muscle of the chicken anterior mesenteric artery

Postnatal development of excitatory innervations in longitudinal smooth muscle of the chicken anterior mesenteric artery

Calcium currents are altered in the vascular muscle cell membrane of spontaneously hypertensive rats.

The dimensional characteristics of smooth muscle in rat blood vessels. A computer-assisted analysis.

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