摘要:

AbstractIn chloralose anesthetized cats blood pressure, heart rate and left ventricular pressure were measured as well as changes in ventricular volume by means of a cardiometer. Hypoxia was induced by ventilating the animal with a gas mixture containing 3 % O2. 1–2 min after the onset of hypoxia cardiac volume started to increase and simultaneously a bradycardia developed. The bradycardia was eliminated by vagal cooling indicating that it was elicited by nervous mechanisms rather than by local myocardial factors. After injection of procaine (0,3–0,5 %) into the cardiometer the afferent vagal fibres from the ventricles could be blocked, leaving the efferent fibres to the sinus node intact. Such selective denervation of the ventricular receptors markedly reduced the bradycardia during hypoxia, suggesting that it is mainly a reflex response emanating from ventricular recept

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05371.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractDextro‐amphetamine (10–5M) added to the medium of rat pineal glands in organ culture produces an eightfold increase of radiolabeled N‐acetylserotonin and melatonin when tryptophan or serotonin are used as labeled precursors. In concentration of 10–4M d‐amphetamine causes a decreased formation of 5‐hydroxyindoleacetic acid from tryptophan and serotonin. Addition of d‐amphetamine to pineal glands also resulted in an increase of N‐acetyltransferase activity as compared with untreated glands. The effect of d‐amphetamine and noradrenaline was blocked by propranolol, a β‐adrenergic blocking agent but not by the α‐adrenergic blocking agent phentolamine. In cervical ganglionectomized rats the addition of d‐amphetamine to the culture medium did not produce an increase in N‐acetylserotonin production. Conversely noradrenaline added to the medium gave a high formation of N‐acetylserotonin. This indicates that the major effects of d‐amphetamine on pineal N‐acetyl‐transferase act

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05372.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractRecordings of the evoked compound potentials in the right main cardiac nerve in the cat demonstrated the presence of both medullated and non‐medullated fibres. The circulatory responses to afferent stimulation of these two fibre populations were followed in terms of changes in blood pressure, heart rate and skeletal muscle and renal flow resistances. A selective stimulation of the medullated afferents, which probably arise mainly from atrial receptors, induced a moderate reflex rise of blood pressure, an increased heart rate and a vasoconstriction in the skeletal muscle and kidney. Clearcut effects were observed first with high stimulation frequencies, and then only in case the buffering influences from other receptor sites were minimized. Stimulation of the non‐medullated fibres, which probably emanate from ventricular receptors, caused a very marked reflex blood pressure fall, slowing of the heart and vasodilatation in the muscle and the kidney, already with very low stimulation rates. These results suggest that the powerful reflex influence from cardiac receptors on the cardiovascular system is exerted by receptors with non‐medullated afferents, while endings firing in medullated pathways ase.g.atrial receptors, have very small direct effects on the cardiovascular system and then rather of an excitatory n

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05373.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractCompared with the rat bone the oxygen uptake by the slices of callus is low during the proliferation of the cartilage in the callus and even lower during the active ossification. The production of lactate by the slices is equal to that of rat bone. These two parameters of the energy metabolism, expressed per whole callus, are maximal on the 9th day after the fracture, corresponding to the degeneration and calcification of the cartilage. Calculated on the weight basis, both parameters decline during the healing. The transition from cartilaginous to ossifying callus is characterized by a drop in the ratio of lactate produced to oxygen consumed. It is concluded that the energy metabolism in regenerating bone is mainly anaerobic thus resembling the granulation tissue.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05374.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe study was performed to clarify whether D‐glucose traverses muscle capillary walls faster than L‐glucose. The transcapillary transport of D‐glucose was slightly faster than that of L‐glucose in experiments at 37° C. The difference in transport rate persisted when the experiments were carried out at 4° C. This indicates that the faster transport of D‐glucose is not due to facilitated transport involving enzymatic steps. It is proposed that the ground matrix of the interendothelial cleft (and of the extravascular space) gives the D‐form of glucose a slight diffusional advantage over the L‐form. A pore effect cannot be compl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05375.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY