Distribution of Norepinephrine in the Heart

Shore, Parkhurst A.; Cohn, Victor; Highman, Benjamin; Maling, Harriet M.

doi:10.1038/181848a0

Cited by 60 publications

(26 citation statements)

References 6 publications

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“…It is possible that some of the differences between atrial and ventricular muscle found in this study, such as the greater velocities and briefer durations in the atrial muscle, are due to the greater concentration of norepinephrine normally found in atrial muscle (30). This difference, however, cannot account for the differences noted in the amount of stretch required to reach L max .…”

Section: Figure 10mentioning

confidence: 71%

Comparison of contractile performance of canine atrial and ventricular muscles.

Urthaler¹,

Walker²,

Hefner³

et al. 1975

Circulation Research

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This study compared the contractile performance of a canine right atrial trabecula with that of a macroscopically indistinguishable trabecula isolated from the right ventricular apex. The heart was removed from nine mongrel puppies weighing 6-8 kg and placed in Krebs-Ringer's bicarbonate solution. The bathing solution contained only 1.25 mmoles of Ca 2+ and was bubbled with a 95% O 2 -5% CO 2 gas mixture. Each atrial trabecula was specially selected from the right atrial appendage. Histologically, these trabeculae showed a remarkable longitudinal orientation of the fibers. At L max (the length of the muscle at which developed tension was maximum) under identical conditions of temperature, rate of stimulation, ionic milieu, pH, and O 2 and CO 2 supply, right atrial trabeculae achieved the same developed and total tensions but in a much shorter time than did ventricular trabeculae. In both muscle groups the maximum developed tension averaged about 2.5 g/mm 2 . Since L o (expressed as a fraction of L max ) was less in atrial muscle than it was in ventricular muscle, we concluded that atrial muscle can be stretched considerably more than can ventricular muscle before optimum length is reached. At any given initial muscle length, the maximum of tension rise for atrial trabeculae amounted to at least twice that for ventricular trabeculae. At any given load up to 1.5 g/mm 2 , the maximum velocity of shortening of an atrial trabecula was about three to four times that of a ventricular trabecula. These results collectively indicate that the contractile performance of the right atrial muscle is in many respects superior to that of the right ventricle, at least under the conditions of these experiments.• The working myocardial cells of the cardiac atria differ morphologically from those of the ventricles (1-14). Atrial myocytes are smaller, branch less often, have fewer if any transverse tubules, and contain specific granules that are not found in ventricular myocytes. There are also significant differences between the pharmacological responses of atrial and ventricular muscles (15,16). Whereas abundant information is available about the mechanical behavior of ventricular myocardium (15-23), much less is known about atrial myocardial performance, and conflicting results have been reported (15,16,24). Differences in the reported results may be due in part to considerable species variability (15, 16) and in part to the fact that published accounts have often failed to emphasize how the results were obtained under significantly different experimental conditions (15, 16). Although dogs are among the most frequently used animals in the experimental cardiovascular laboratory, we can find no report comparing the mechanical properties of canine right atrial and right ventricular trabeculae. This work was supported by U. S. Public Health Service Grant HL 11,310 from the National Heart and Lung Institute and by MIRU Contract 4367-1441.Received March 10, 1975. Accepted for publication September 12, 1975. The present study...

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Section: Figure 10mentioning

confidence: 71%

Comparison of contractile performance of canine atrial and ventricular muscles.

Urthaler¹,

Walker²,

Hefner³

et al. 1975

Circulation Research

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“…On the other hand, the atrium, especially the right atrium, contains more transmitter substance, NA, than the ventricular myocardium in various species of animals (Muscholl, 1959;Cervoni, Kirpekar & Schwab, 1966). In the dog, Shore, Cohn, Highman & Maling (1958) have found that the sinus node region contains 2.3 ,g/g NA, while the right papillary muscle contains 1.5 ,g/gram. Angelakos, Fuxe & Torchiana (1963) have further shown histochemically that the catecholamines were located in nerve structures and that a high density of fluorescent fibre bundles were found in the sinus node region of the rabbit.…”

Section: Mechanism Ofaction Of Dopaminementioning

confidence: 97%

EFFECTS OF DOPAMINE ON SINUS RATE AND VENTRICULAR CONTRACTILE FORCE OF THE DOG HEART in vitro AND in vivo

Endoh

1975

British J Pharmacology

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1 Experiments were carried out on dog isolated papillary muscle and sinus node preparations perfused with arterial blood from a donor dog. The chronotropic and inotropic effects of dopamine were analysed by using reserpine, desmethylimipramine (DMI), cocaine and phenoxybenzamine, and the relative chronotropic and inotropic effects defined, the results being compared with those for noradrenaline (NA). 2 The effects of dopamine administered intra-arterially into the isolated preparations were reduced by pretreatment of animals with reserpine both in the papillary muscle and sinus node. The chronotropic effects, however, were affected less by pretreatment with reserpine than were the inotropic effects. 3 Desmethylimipramine (DMI) reduced the inotropic and chronotropic effects of dopamine, and enhanced the effects of NA and nerve stimulation; the chronotropic effects of the amines were less affected than the inotropic effects. 4 Cocaine enhanced considerably the inotropic and chronotropic effects of NA, and decreased the inotropic but not the chronotropic effect of dopamine. 5 Phenoxybenzamine enhanced the inotropic effects of dopamine, NA and nerve stimulation, but did not affect the chronotropic effects of the amines.6 When dopamine (1 to 300Mg/kg) was administered intravenously to the donor dog, it increased preferentially the contractile force of the ventricular myocardium with a comparatively small change of the sinus rate in the isolated preparations as well as in the heart in vivo. NA (0.1 to 10;Mg/kg) caused effects similar to those of dopamine. The maximal inotropic responses to these catecholamines were reached with lower doses than the chronotropic ones. 7 It is concluded that both the positive inotropic and the positive chronotropic responses to dopamine are mediated partially by a direct and partially by an indirect stimulant effect on p-adrenoceptors in the dog heart. The present results suggest that the difference in activity of dopamine and NA between the ventricular myocardium and the sinus node may be ascribed to the unequal innervation with adrenergic nerve fibres of the atrium and the ventricle (Furnival, Linden & Snow, 1971). The sinus node which is densely innervated by adrenergic nerve fibres may inactivate noradrenaline and dopamine more effectively than the ventricular myocardium through the uptake into the nerve and thereby be less sensitive to the exogenous catecholamines.

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“…It has been shown that the heart of the mammals contains relatively large amount of catecholamines, mainly consisting of noradrenaline (1)(2)(3)(4)(5). The cardiac tissue takes up exogenously administered noradrenaline (6)(7)(8) and stores it for relatively long periods of time (6,9,10).…”

mentioning

confidence: 99%

The Effects of Stellate Ganglionectomy on the Distribution, Uptake and Storage of Noradrenaline in the Dog Heart

Hara

1966

Japanese Journal of Pharmacology

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It has been shown that the heart of the mammals contains relatively large amount of catecholamines, mainly consisting of noradrenaline (1-5). The cardiac tissue takes up exogenously administered noradrenaline (6-8) and stores it for relatively long periods of time (6, 9, 10).The sympathectomy causes marked depletion of catecholamines in the sympathetic nerve terminal. Remarkable depletion of the cardiac catecholamines caused by the stellate ganglionectomy in the cat (11) suggests the dominant participation of the post ganglionic fibers originating in, or craniad to, the stellate ganglion, to the sympathetic innervation on the heart. In the dog, on the other hand, cardiac catecholamines are hardly depleted by bilateral resection of the stellate ganglion and thoracic sympathetic chain and ganglia, but depleted by extensive resection of the nerve plexus adjacent to the heart (12). On the basis of the physiological studies, Pannier (13) has indicated that the sym pathetic cardiac accelerance nerves of the dog, at least in some part, pass through the stellate ganglion without changing neuron.The following experiments were performed in an attempt to know how is the capa city of the dog heart to take up and store exogenously administered noradrenaline affected by the stellate ganglionectomy which causes only partial decreases in endogenous noradrenaline levels. METHODSMongrel dogs weighing 5 to 8 kg and of either sex were used. Determination of ' noradrenalineThe dogs anesthetized with pentobarbital sodium (40 mg/kg, i.p.) were killed by ex sanguination from the femoral arteries. Immediately the heart was removed and cleaned up by perfusion through the coronary vessels with chilled Tyrode's solution. Then the heart was divided into following portions: right (RA) and left (LA) atrium, right (RV) and left (LV) ventricle and ventricular septum (VS). Both the RV and LV were sub divided into the ventral and dorsal wall by vertical cutting. After blotting with filter paper and weighing, the tissue pieces were minced and homogenized in cooled 0.4 N

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Distribution of Norepinephrine in the Heart

Cited by 60 publications

References 6 publications

Comparison of contractile performance of canine atrial and ventricular muscles.

Comparison of contractile performance of canine atrial and ventricular muscles.

EFFECTS OF DOPAMINE ON SINUS RATE AND VENTRICULAR CONTRACTILE FORCE OF THE DOG HEART in vitro AND in vivo

The Effects of Stellate Ganglionectomy on the Distribution, Uptake and Storage of Noradrenaline in the Dog Heart

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