The adrenergic innervation of the cardio-vascular system of the lizard Trachysaurus rugosus

Furness, John B.; Moore, Joanne I.

doi:10.1007/bf00335293

Cited by 22 publications

(3 citation statements)

References 24 publications

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“…Although the adrenergic innervation of various parts of the arterial tree is not uniform in density (7)(8)(9), it is found characteristically at the adventitiomedial junction (1,7,8,10,11). A number of exceptions to this pattern have been documented (1,(12)(13)(14)(15)(16)(17)(18), but their significance or consequence has not been studied.…”

Section: Discussionmentioning

confidence: 99%

Variations in Adrenergic Innervation and Contractile Responses of the Rabbit Saphenous Artery

Bevan

Purdy

1973

Circulation Research

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The Falck fluorescence histochemical method was used to compare the adrenergic innervation in segments from the proximal saphenous artery, the distal saphenous artery and the popliteal artery. Adrenergic neurons penetrated the media of the proximal saphenous artery but not that of the distal saphenous artery or the popliteal artery. Responses of these vessel segments to exogenous Z-norepinephrine and to electrical stimulation of their intramural innervation were measured. The median effective dose (ED 50 ) of Z-norepinephrine was ten times greater in the proximal saphenous artery than it was in the distal saphenous artery and the popliteal artery. The response of the proximal saphenous artery to neural stimulation was nearly double that of the distal vessel and required one-fifth of the time to achieve maximum tension; the response of the popliteal artery was negligible due to its low density of innervation. The three-dimensional medial distribution of the adrenergic neuronal plexus in the proximal saphenous artery should (1) increase the efficiency of neuronal uptake of Z-norepinephrine and thereby account for the increased ED B0 of Z-norepinephrine, and (2) decrease the mean distance between adrenergic nerves and medial smooth muscle cells. Therefore, transmitter would accumulate more rapidly and reach a higher level in the media during neural activity. KEY WORDSadrenergic transmission vasoconstriction neurogenic response norepinephrine diffusion sympathetic transmitter• The adrenergic innervation of most blood vessels is limited to the adventitio-medial junction (1). However, a survey of the pattern of adrenergic innervation of arteries of the rabbit by a fluorescence histochemical technique has shown that adrenergic neurons penetrate the outer one-half to two-thirds of the media of the proximal saphenous artery (2). Furthermore, the distribution of the adrenergic plexus is not uniform along the length of this artery. At the distal end of the vessel the innervation is restricted to the adventitio-medial junction. Therefore, the distribution of adrenergic innervation was studied in detail along the entire length of the saphenous artery and along the adjacent proximal portion of the popliteal artery. Variations in the pattern of adrenergic innervation of these arteries were related to differences in their responses to sympathetic stimulation in vitro. This work was supported by U. S. Public Health Service Grant HE-08359 from the National Heart and Lung Institute and by Los Angeles County Heart Association Grant 4081G. Mr. Purdy was supported by U. S. Public Health Service Training Grant GM 02040.Received November 9, 1972. Accepted for publication April 5, 1973. MethodsNew Zealand rabbits weighing 2.5-3.0 kg were killed and exsanguinated; vessels were removed for functional and histological study.Vessel ring segments, 1 mm in length after excision, were mounted in vitro to record changes in wall tension using the method of Bevan and Osher (3). Doses of Znorepinephrine were added sequentially directly to ...

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Section: Discussionmentioning

confidence: 99%

Variations in Adrenergic Innervation and Contractile Responses of the Rabbit Saphenous Artery

Bevan

Purdy

1973

Circulation Research

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“…At first, differences in the density of sympathetic terminals along the aorta were supposed to underlie this gradient of response. Morphological studies dealing with the vasomotor innervation of the aorta in vertebrates acquired by histo-chemical or electromicroscopic methods (27)(28)(29)(30)(31) do not clarify the question. Our own determination of the monoaminergic innervation of both proximal and distal segments of the abdominal aorta, using the histochemical method, however, established no substantial differences either in the density or in the distribution of sympathetic terminals in the aortic wall.…”

Section: Discussionmentioning

confidence: 99%

Sympathetic Control of Canine Abdominal Aorta

Gerová

Gero

Dolezel

et al. 1973

Circulation Research

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In anesthetized dogs the peripheral ends of the cut sympathetic chains (LGi-LG 2 level) were stimulated while blood pressure was held constant artificially, and the diameter of the abdominal aorta was monitored. Bilateral stimulation induced a reduction in diameter that was directly related to the stimulation frequency. Maximal diameter reduction of the aorta above the iliac bifurcation averaged 8.01 ± 0.74* of resting diameter. The half-time of contraction (36.5 ±2.1 to 51.5 ± 3 . 6 seconds) was indirectly related to the stimulation frequency. The effects of right or left sympathetic chain stimulation were quantitatively similar to each other (51.3 ± 4.4% and 46.7 ± 4.5%, respectively), and the response to bilateral stimulation (92.8 ±6.1&) did not differ from the calculated value for paired unilateral stimulation (100%). A significant proximo-distal gradient of response (below the branching off of the renal arteries 2.97 ± 0.28%, at the midpoint 5.15 ± 0.52%, and above the iliac bifurcation 8.56 ± 0.79% of resting diameter) along the abdominal aorta was established during bilateral stimulation. Histochemical examination showed no corresponding differences in the density or the distribution of monoaminergic terminals. Dose-response relations for spiral strips taken from analogous aortic segments, however, displayed sensitivity to norepinephrine in the same order as the gradient in the in vivo experiments.diameter. Particularly, the range of sympathetic control of the diameter of the aorta was investigated and the functional peculiarities of the bilateral innervation were examined. In addition, the response to sympathetic stimulation along the abdominal aorta was monitored. Finally, to explain the established differences in responsiveness, both pharmacological experiments and histochemical studies were performed. MethodsExperiments were performed on 32 adult mongrel dogs of either sex weighing 11.0-19.0 kg. The dogs were anesthetized with sodium thiopental (10-15 mg/kg, iv) at the beginning of the experiment, and supplementary doses (4-7 mg/kg) were given hourly.To minimize blood losses all surgery was performed with electrocautery. After opening the abdomen with a midline incision from the xiphoid process down to the symphysis, the intestines were drawn to the left side and covered with warmed wet cotton.In 16 dogs the aorta was left intact and normally tethered except at the site where diameter was registered; at this site it was freed for a distance not longer than 5 mm. In all dogs the diameter was recorded 15-20 mm above the iliac bifurcation closely distal to the origin of the caudal mesenteric artery; the cross section of the aorta is circular at this point. In 6 dogs diameter and pressure were monitored at three sites, Site 1 was 15-20 mm above the iliac bifurcation,

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“…the caval veins, sinus venosus, auricles, ventricle, and coronary arteries of reptiles (Furness and Moore, 1970). Catecholamines produce both posi tive chronotropic and inotropic responses in reptiles (Akers and Peiss, 1953;Kirby and Burnstock, 1959b).…”

Section: U * M C Y It; Uiic Uibbucb Ui Uiv Iiymentioning

confidence: 99%

Cardiovascular responses to diving in the turtle, Pseudemys scripta

Ware¹

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The adrenergic innervation of the cardio-vascular system of the lizard Trachysaurus rugosus

Cited by 22 publications

References 24 publications

Variations in Adrenergic Innervation and Contractile Responses of the Rabbit Saphenous Artery

Variations in Adrenergic Innervation and Contractile Responses of the Rabbit Saphenous Artery

Sympathetic Control of Canine Abdominal Aorta

Cardiovascular responses to diving in the turtle, Pseudemys scripta

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