Ontogenic development of the renal ornithine decarboxylase response to testosterone

Summary In neonatal mice, renal ornithine decarboxylase was not altered by testosterone injection, in contrast to adult mice in which the enzyme was greatly elevated following treatment with testosterone.     

Altered hyperemic response of the coronary arterial bed in alloxan-diabetes

Reactive hyperemic responses of the coronary arterial bed, provoked by asphyxia or clamping of the coronary artery, were compared in alloxan-diabetic and metabolically healthy dogs. In alloxan-diabetic dogs the response of the coronary arterial bed lasted longer, and its reactivity to hypoxia was lower. Treatment with adenosine caused less vasodilation in diabetic animals than in controls. These changes may be due to the altered reactivity of diabetic vascular smooth muscle.     

Altered hyperemic response of the coronary arterial bed in alloxan-diabetes

Summary Reactive hyperemic responses of the coronary arterial bed, provoked by asphyxia or clamping of the coronary artery, were compared in alloxan-diabetic and metabolically healthy dogs. In alloxan-diabetic dogs the response of the coronary arterial bed lasted longer, and its reactivity to hypoxia was lower. Treatment with adenosine caused less vasodilation in diabetic animals than in controls. These changes may be due to the altered reactivity of diabetic vascular smooth muscle.     

The influence of the experimental conditions on the renal response to angiotensin in the rat

Résumé Les conditions expérimentales déterminent la réponse rénale à l'angiotensine chez le rat. Antérieurement, on a seulement demontré une réponse natriurétique à cette hormone. Cependant, chez les rats chargés chroniquement de sodium, on a demontré que l'angiotensine en doses de 0,00005–0,005µg/kg/min est toujours anti-natriurétique. Après une opération récente, ou sous anesthésie ou en présence d'une déplétion de sodium, l'angiotensine à ces doses, chez les mêmes animaux, est soit sans effet ou même natriurétique.     

Influence of age on the renal renin response to a high salt intake in the rat

Summary Saline drinking combined with DOCA-treatment was found to decrease renal renin in weanlings at a higher rate than in adult rats, with a comparable saline consumption level. The decrease was not potentiated by uninephrectomy.     

Influence of age on the renal renin response to a high salt intake in the rat

Saline drinking combined with DOCA-treatment was found to decrease renal renin in weanlings at a higher rate than in adult rats, with a comparable saline consumption level. The decrease was not potentiated by uninephrectomy.     

Use of indomethacin to reverse neonatal hypotension

Summary Treatment with indomethacin elevated systemic arterial pressure and pulmonary vascular resistance in hypotensive newborn goats. Indomethacin may be of value in restoration of systemic arterial pressure in stress-induced hypotension.Supported in part by Nos. NIH-HL-10834-06, NIH-T01-HL05979-02S1 and Florida Heart No. 74-AG-2.Acknowledgments. The authors wish to thankN. L. Murtha, L. Tumarkin, J. Howard andP. Eitzman for their technical assistance and Merck, Sharpe and Dohme for the gift of indomethacin. This research was conducted under the guiding principles in the care and use of animals approved by the Council of the American Physiological Society and the National Institute of Health.     

Intrarenal circulation in hemorrhagic hypotension

Zusammenfassung Durch simultane Ermittlung der totalen und der nutritiven Nierendurchblutung, sowie der PAH-Extraktion und -Sekretion, wurde festgestellt, dass während einer hämorrhagischen Hypotonie (1) der Nierenwiderstand ansteigt, (2) der relative Anteil der Markdurchblutung unverändert bleibt und (3) etwa 15% der gesamten Durchblutung in der Rinde durch arteriovenöse Anastomosen geleitet wird bzw. die peritubulären Kapillaren vermeidet.     

Mechanism of the hypotension during the antabuse-alcohol reaction in rabbits

Résumé Nos études sur le système circulatoire des lapins anesthésiés à l'uréthane montrent que la baisse de la résistance vasculaire périphérique, provoquée par un facteur transporté par le sang, est une cause majeure contribuant à l'hypotension pendant la réaction Antabuse-Alcool. Aucune évidence de la présence d'un bloc primaire au niveau du système vasoconstricteur n'a été constatée.     

Primary cilia elongation in response to interleukin-1 mediates the inflammatory response

Primary cilia are singular, cytoskeletal organelles present in the majority of mammalian cell types where they function as coordinating centres for mechanotransduction, Wnt and hedgehog signalling. The length of the primary cilium is proposed to modulate cilia function, governed in part by the activity of intraflagellar transport (IFT). In articular cartilage, primary cilia length is increased and hedgehog signaling activated in osteoarthritis (OA). Here, we examine primary cilia length with exposure to the quintessential inflammatory cytokine interleukin-1 (IL-1), which is up-regulated in OA. We then test the hypothesis that the cilium is involved in mediating the downstream inflammatory response. Primary chondrocytes treated with IL-1 exhibited a 50% increase in cilia length after 3 h exposure. IL-1-induced cilia elongation was also observed in human fibroblasts. In chondrocytes, this elongation occurred via a protein kinase A (PKA)-dependent mechanism. G-protein coupled adenylate cyclase also regulated the length of chondrocyte primary cilia but not downstream of IL-1. Chondrocytes treated with IL-1 exhibit a characteristic increase in the release of the inflammatory chemokines, nitric oxide and prostaglandin E2. However, in cells with a mutation in IFT88 whereby the cilia structure is lost, this response to IL-1 was significantly attenuated and, in the case of nitric oxide, completely abolished. Inhibition of IL-1-induced cilia elongation by PKA inhibition also attenuated the chemokine response. These results suggest that cilia assembly regulates the response to inflammatory cytokines. Therefore, the cilia proteome may provide a novel therapeutic target for the treatment of inflammatory pathologies, including OA.     

Changes in the lumen of coronary vessels under oligemic hypotension

Conclusions The decrease of circulating blood volume, resulting in oligemic hypotension, may evoke in anaesthetized cat the active constrictory coronary vessel responses of 2 types, one occuring immediately after start of the hypotension and the other having a significantly prolonged latency.

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The influence of hypertension upon the normal cardiovascular responses to hemorrhagic hypotension and shock

The data suggest that rats genetically inbred to be hypertensive (SHR) are less able to compensate for hemorrhage and shock than their normotensive controls (WKY). Two reasons for this genetic dysfunction are: 1) SHRs seem to depend more on innervated alpha 1 than noninnervated alpha 2 adrenoreceptors for vasoconstriction; and 2) the vascular smooth muscle hypertrophy noted in SHRs may interfere with effective vasoconstriction.     

Direct autonomic nerve fibers to the renal medulla in man

Résumé Des fibres nerveuses passent directement du plexus nerveux des artères arcuates aux artérioles efférentes juxtamédullaires et aux vasa recta. Il est donc possible, que le contrôle neural de la distribution du sang entre le cortex et la medulla soit indépendant du passage du sang aux glomeruli.

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This investigation was supported by the Medical Research Council of Canada, Grant No. MA-3169.