摘要:

AbstractExperiments, with recording of gastric volume, were performed in chloralosed cats. Topical hypothalamic stimulations produced vagally mediated increases in volume by two mechanisms. One type of response, due to central inhibition of vagal excitatory tone was induced from the defence area and eliminated by atropine or vagotomy. The other type of response, far less commonly encountered, remained after atropine and spinal cord section, but was abolished by vagotomy. The latter type was not induced from any well defined hypothalamic region, and had a high stimulation threshold. While sham feeding in conscious cats with esophagostomy and gastrostomy induced prompt, marked and longlasting gastric volume increases in connection with swallowing, such responses were not evoked as “anticipatory” reaction to food intake. The relaxations could be prevented by vagotomy but not by guanethidine nor atropine. It is concluded that the vagally mediated relaxation in connection with sham feeding occurs mainly from activation of mechanoreceptors and that the hypothalamic control over the vagal relaxatory fibres is probably mi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05784.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe disappearance of3H‐corticosterone from the serum was measured in obese‐hyperglycemic mice and their lean litter mates of various ages. At 1 month of age the serum half‐life of the injected tracer was the same in the obese and lean animals. In the 2, 5 and 12 months old mice the tracer hormone disippeared faster in the obese mice than in their lean controls. The present results confirm that the previously observed enlargement of the adrenal cortex and the increased secretion of corticosteroids by adrenal glandsin vitroin fact indicate a considerably hyperadrenocorticism in the obese mouse. Furthermore, the difference in disappearance rate of corticosteroidsin vivobetween obese and lean mice approximately parallels the age variation of the other metabolic abnormalities of the syndrome suggesting that the hyperadrenocorticism is part of the multiendocrine disturbance which manifests itself as the obese‐hyperglycemic s

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05785.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe isolated rabbit heart was perfused according to the Langendorff technique. Prostaglandins in the effluent from the organ were identified by use of thin layer chromatography and assayed on the rat stomach strip, The effect of alterations of the physical and chemical conditions of the perfusion medium on the overflow of prostaglandins from the heart was studied. In addition, the capacity of noradrenaline and acetylcholine to release prostaglandins was tested. Acidosis, hyperthermia. hypothermia, hypotension, hyperosmolarity and increased [K+] or [Ca++] levels, while all inducing marked changes in the mechanical activity of the heart, did not induce prostaglandin release. Hypoxia, on the other hand, stimulated the liberation of prostaglandins. Noradrenaline was a potent agent for stimulation of prostaglandin release, in the absence of alpha‐ and betaadrenergic receptor blockade. Acetylcholine was also found to liberate prostaglandins, by activation of muscarinic receptors. The prostaglandin releasing capacity of acetylcholine was about 3 times weaker than that of noradrenaline. It is concluded that the release of prostaglandins from the rabbit heart is not dependent on the mechanical activity of the organ. Furthermore, it is suggested that prostaglandins released by hypoxia may play an important role in the development of reactive hyperemia. Finally it is stated that the release of prostaglandins from the heart caused by acetylcholine may constitute the negative link in an endogenous prostaglandin mediated feed‐back inhibition of the release of acetylcholine from parasympathetic nerve endi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05786.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractArterial and venous plasma glucose concentration was determined at intervals in cats subjected to hemorrhagic hypotension at 50 mm Hg. The rapid rise of arterial plasma glucose after hemorrhage could be. attributed to an increased release of glucose from the liver. This hyperglycemia could not be eliminated by bilateral adrenalectomy or by sectioning of the hepatic sympathetic nerves, although the response was somewhat depressed by the latter procedure. On the other hand the hyperglycemia was virtually abolished after adrenalectomy when combined with bilateral sectioning of the major and minor splanchnic nerves. The level of plasma glucagon during hemorrhage increased in cats with an intact sympatho‐adrenal system, but was unchanged in animals with combined splanchnic sympathectomy and adrenalectomy. It is concluded that, during hemorrhage, the sympatho‐adrenal system influences the glucose output from the liver by three different reflex mechanisms: (a) release of catecholamines from the adrenal glands; (b) direct sympathetic nerve influence on the liver; and (c) release of glucagon from the pancr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05787.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractCardiovascular responses to carotid body chemoreceptor stimulation were followed in the ‘curarized’, vagotomized, artificially ventilated cat. Stimulation of the chemoreceptors by perfusion of the carotid sinus regions with venous blood induced a reflex vasoconstriction in skeletal muscle, kidney, intestine and skin, and, in most cases, an increased heart rate. A comparison of the chemoreceptor reflex responses with those obtained by direct electrical stimulation of the regional vasomotor fibres indicated that in chemoreceptor reflexes the vasomotor fibre activity increased to the same extent in skeletal muscle and intestinal resistance vessels and, probably, in the ‘nutritional’ skin vessels but to a smaller extent in the renal vessels and the skeletal muscle capacitancc vessels. The renal vessels and the muscle capacitance vessels seemed, however, to respond more during chemoreceptor stimulation than when the baroreceptors were unloaded, indicating that an excitation of the bul bar vasomotor centre is more effective than the withdrawal of an inhibitory restraint in activating the vasomotor fibres to these vascular s

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05788.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe administration of egg albumin to rabbits sensitized to this antigen caused marked increases in the arterial concentration of lactate, glucose and glycerol, but no change in the arterial FFA level. Antigen administration had no effect in non‐sensitized rabbits. Phentolamine (3 mg/kg) or propranolol (1 mg/kg) did not significantly alter the responses to egg albumin in sensitized rabbits. Noradrenaline or sympathetic nerve stimulation decreased blood flow but caused no significant change in lipolysis in rabbit epigastric adipose tissuein situ. It is therefore questionable if catecholamines are the major cause of the observed metabolic consequences of the anaphylactic reaction in the rabbit. These metabolic events,i.e. increased lactate levels, lipolysis, and reesterification of fatty acids, are similar to those reported during hemorrhagic or endotoxin shock in dogs, in spite of species‐differences and the difference in the genesis of the sh

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05789.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractPrevious reports on the fetal hypoxic bradycardia in animals have indicated, that there is a vagal influence, especially when asphyxia is induced by umbilical cord occlusion. In the present study hypoxia was inducedoiathe mother, thus keeping the fetal circulation intact. The experiments were conducted on mature fetuses of three different species, namely 20 guinea‐pig, 3 cat and 3 lamb fetuses. The ECG was recorded continuously and used for measuring the fetal heart rate. The vagal influence on the fetal hypoxic bradycardia was tested by comparing the time for the onset of the bradycardia with or without vapl activity. There was no indication of any vagal component in the fetal hypoxic bradycardia, which is therefore to be regarded rather as a sign of myocardial hypoxia and failing fetal circulation. The ECG recordings showed that the fetal bradycardia initially is an AV‐block, type II, and that there are progressive changes in the S‐T interval as an early sign of hy

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05790.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractA method for continuous recording of the ionic efflux from frog skin glands has been developed which under given experimental conditions provides a convenient index on glandular secretion. A nerve skin preparation from the calf is mounted so that the outside of the skin forms the bottom of a small test compartment with distilled water while the corium side is bathing in Ringer's solution. After determination of the adequate nerve stimulus parameters for discernible gland secretion to occur, the skin nerve was stimulated at 10 Hz during varying periods and chemical control analyses performed of the changes in ionic content of the test compartment solution. The main ionic outflow consisted of Na+and Cl‐in equal amounts, the outflow of other ions during stimulation being negligible. The concomitant conductance changes were measured as variations of absorption in a high‐frequency field applied to a conductance probe placed in the test chamber. Determinations of the NaCl outflow based on the conductance changes were in good agreement with the values obtained by chemical analysis. The continuous conductance recordings proved to give approximative information of the quantities and time relations of the glandular secretion, allowing a direct comparison with,e.g., skin potential chan

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05791.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe effect of bradykinin on gastric and colonic motility was studied in anaesthetized cats with volume recording devices and compared with the effects of vagal nerve stimulation. When administered intra‐arterially bradykinin caused a profound and prolonged gastric relaxation. Simultaneously there was a marked and likewise prolonged colonic contraction. The gastric relaxation closely mimicked the atropine resistant relaxation elicited by vagal nerve stimulation. These effects could not be blocked by antiadrenergic drugs and it is suggested that bradykinin and the unknown transmittor substance(s) released on vagal stimulation act in a similar way on the gastric smooth muscles and that a kinin mechanism may be involved in the vagal response. As regards the colonic motor response it was shown that bradykinin does not reproduce the vagal motility effects on colon smooth muscle but mimicks closely the atropine resistant expulsive contraction elicited by activation of the pelvic nerve

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05792.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe possible central integrative mechanisms, responsible for the earlier reported, differentiated reflex engagement of the renal and muscle vessels and the heart from cardiac ventricular receptors and arterial baroreceptors, respectively, were analyzed in atropinized cats. The reflex renal vessel, muscle vessel and heart rate responses, expressed as per cent of maximum, to graded activations of arterial baroreceptors (sinus pressure variations) and stimulations of ventricular receptor afferents in the cardiac nerve were systematically compared. Cardiac nerve stimulation with low frequencies was found to elicit more pronounced reflex renal vessel responses than muscle vessel and heart rate responses. In contrast, elevations of sinus pressure induced equally pronounced renal and muscle vessel responses. High frequency cardiac nerve stimulation elicited maximal reflex renal vessel responses, but only submaximal effects on muscle vessels and heart rate, while intense baroreceptor stimulation induced maximal reflex effector responses throughout. The submaximal heart rate response to cardiac nerve stimulation is probably due to a simultaneous activation of excitatory afferents. On the other hand, the less pronounced muscle than renal vessel responses when the cardiac nerve was stimulated probably reflect a relatively sparse innervation of muscle vasomotor neurons by ventricular receptor afferents, which seem instead to be preferentially oriented towards renal vasomotor and, possibly, cardiac motor neurons.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05793.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY