摘要:

AbstractA technique for simultaneous i.v. infusion into and blood and urine sampling from relatively unrestrained rats. Detailed description of the design of catheters, of their implantation and of sampling procedures. Control autopsy results are discussed.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04369.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractExperiments were performed on chloralosed, adrenalectomized cats with recording of gastric volume, blood pressure and skeletal muscle blood flow. The vagal nerves were cut, but the vagal excitatory fibres to the stomach could be activated by electric stimulation. Topical stimulation of the hypothalamic defence area, or surrounding “pressor” areas, produced not only the characteristic known circulatory responses, but also a prompt and often complete inhibition of a vagally induced increase of gastric motility.‐But when the stomach wasnotunder the influence of continuous vagal excitatory activity, corresponding stimulation of the hypothalamus rarely had any effect on gastric volume, and then only an insignificant and sluggish increase despite considerable “myogenic” tone of the stomach. Stimulation of the adjacent hypothalamic sympatho‐inhibitory area, on the other hand, augmented the vagally induced gastric motility and thereby suggested the presence of a centrally induced suppression of a prevailing sympathetic inhibitory influence on the stomach.‐All the above mentioned effects on gastric volume, produced by central nervous stimulation, could be blocked by guanethidine in these vagotomized cats. It is concluded that the hypothalamus contains neural mechanisms, which can affect stomach motility by changing in both directions the impulse frequency in the inhibitory adrenergic outflow to this organ. Simultaneous activity of vagal excitatory fibres to the stomach was found to be a prerequisite for reducing significantly gastric motility and tone when the adrenergic fibres were excited. This is compatible with the hypothesis that the adrenergic fibres exert their inhibitory effect mainly, or only, by acting on the parasympathetic ganglionic cells, which mediate the vagal excitatory influence to the gastric s

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04370.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIn isolated rat diaphragm suspended in a buffer solution where Na+ had been exchanged for K+ or choline the basal phosphorylaseaactivity was reduced and the phosphorylaseaactivating effect of adrenaline and isoprenaline was blocked or reduced. The total phosphorylase activity and the level of high energy phosphate compounds were unchanged in high‐K+ buffer but the former reduced in choline buffer. The basal phosphorylaseaactivity was reduced in a Ca++‐free solution but the effect of adrenaline was unchanged. The phosphorylaseaactivating effect of the catecholamines is mediated by adenosine 3′,5′‐monophosphate (cyclic AMP). Addition of cyclic AMP to the buffer solution had a stimulating effect on the phosphorylaseaactivity of the rat diaphragm. This effect was blocked or reduced when Na+ in the buffer solution was exchanged for K+ or choline. It has been demonstrated that the stimulating effect of adrenaline on the cyclic AMP content in the diaphragm is unchanged in high‐K+ media. We suggest that the blockade of the phosphorylaseaactivating effect of the catecholamines in high‐K+ media was due to an inhibition of the action

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04371.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractCanaries were used as experimental animals. The birds were kept singly. Each cage was separately illuminated. The light could be extinguished by the bird if it used one perch in the cage. As darkness corresponds to rest in adapted birds the self‐selected circadian rhythm of rest and activity could be recorded. The waking‐up times were used as the starting point of the circadian period. L‐triiodothyronine (T3) was given as a single dose at different times during the activity. Oral doses up to 10 mg/kg given early in the activity did not influence the length of the circadian period. There was an uncertain increase in activity. Similar doses given late in the activity increased the length of the circadian period. The duration of activity was increased and the rest was decreased. The changes were maximal in the period after the one in which T3 was given and gradually disappeared during approximately a week. The effects on the circadian period seemed to be related to the amount of T3 given, in the dose interval used (1–10 mg/kg). The increase in activity was less influenced by the amount of T3. Parenteral administration of 1 mg/kg T3 late in the activity caused changes corresponding to those induced by 6–8 mg/kg orally. The magnitude of the maximal increase in duration of circadian period and activity was independent of the pre‐experimental value. Thyrotropic hormone (1–2 IU) in a few birds caused a small increase in the duration of the circadian period in which

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04372.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe development of three monoamine‐storing cell systems in the wall of the duodenum, glandular portion of stomach, and ileum has been followed histochemically in fetal and newborn rats, and compared with the number and characteristics of such cells in adults. 5‐Hydroxy‐tryptamine can be demonstrated in mast cells and enterochromaffin cells already a few days before birth. Part of the mast cell population,i.e.the one which in adult animals is found as “atypical” mast cells near the mucosal surface, is able to take up high amounts of L‐DOPA. “Enterochromaffin‐like” cells, exclusively found in the oxyntic gland area of the gastric mucosa, are also able to take up and, probably decarboxylate, L‐DOPA already at birth. Their number increases progressively in the following stages. Gastric DOPA decarboxylase activity is high already at a stage when the capacity to store monoamines has not yet developed in the enterochromaffin‐like cells, the system of monoamine cells quantitatively dominating in the stomach wall. The finding suggests that DOPA decarboxylase occurs also in other cell systems, such as mast cells and enterochromaffin cells, which are capable of storing monoamines earlier than the enterochromaffin‐like cells. The activity of gastrointestinal DOPA decarboxylase reaches adult levels already by the time of birth, and is probably primarily associated with the two systems of enterochromaffin and ente

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04373.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIn an attempt to trace the phylogenetical origin of stimulatory (constrictive) and inhibitory (dilatatory) actions of histamine and 5‐hydroxytryptamine on mammalian vascular smooth muscle, the vascular responses to these drugs were studied in jawless vertebrates and fish. Effects were recorded as blood pressure changes in dorsal and ventral aorta after intravascular administration of drugs, and as resistance changes in artificially perfused branchial and systemic blood vessels after administration into the perfusion circuit. The reliability of experimental procedure and recording technique was tested by observing the presence of responses to adrenaline, noradrenaline or acetylcholine. Pharmacological blocking agents were used to dissociate between specific and unspecific actions. In jawless vertebrates, the vascular effects of histamine and 5‐hydroxytryptamine seemed to reflect unspecific actions on adrenergic receptor mechanisms. The effects in cartilaginous fish were slight. Characteristic effects, produced by specific stimulatory actions on vascular smooth muscle, appeared in higher bony fish. Inhibitory actions were not revealed in any species. By comparing the results obtained in intact animals with those from perfused preparations, it may be concluded that stimulatory actions of 5‐hydroxytryptamine appear as a constrictor response in the branchial blood vessels of teleosts, while the stimulatory actions of both histamine and 5‐hydroxytryptamine are fully developed and produce vasoconstriction in all studied sections of the vascular system in l

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04374.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effects of stepwise rises in plasma potassium concentration on the pressor responses to short (less than 3 min) periods of ventilation hypoxia and to vasoconstrictor agents, were investigated in isolated blood‐perfused rat lungs. Both hypoxia‐responses and drug‐responses were potentiated. Plasma potassium ion concentrations above 17.0 to 18.8 meq/l caused dose‐dependent sustained elevations of pulmonary vascular resistance (PVR). Ventilation hypoxia superimposed on such high PVR did still cause brisk pressor responses. Potassium‐induced vasoconstriction were obtained also in periods with no pressor responses to ventilation hypoxia i.e. by cooling of the perfusate or late in a perfusion. The results suggest that a reduction of the vascular smooth muscle cell ratio [K+]i/[K+]0by hypoxia‐induced transcellular leakage of potassium‐ions is not the sole mechanism for the pressor response to acute ventil

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04375.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractIn acute experiments on chloralosed cats gastric motility was recorded with a rubber balloon system kept at constant intragastric pressure under experimental conditions not requiring abdominal surgery.‐Electric stimulation of the central end of either a small vagal branch at the level of the diaphragm or of one vagal nerve at the level of the neck, while the opposite vagal nerve was left intact produced profound reflex relaxation of the stomach. Also the efferent pathway of the relaxatory reflex was in the vagal nerves.‐The reflex relaxation persisted after administration of atropine, which shows that it was not due to reflex suppression of prevailing activity of the vagal cholinergic motor fibres. It was also independent of adrenergic mechanisms, since it persisted after administration of guanethidine in doses known effectively to block the adrenergic intestino‐gastric inhibitory reflex. This vago‐vagal relaxatory reflex response thus showed the same characteristics as the gastric response elicited by efferent stimulation of the high‐threshold vagal relaxatory fibres.‐It is concluded that this vago‐vagal reflex originates, at least partly, from abdominal structures, with the efferent pathway consisting of the relaxatory, high‐threshold fibres producing pronounced gastric relaxation. This vago‐vagal relaxatory reflex may be involved in receptive relaxati

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04376.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Earlier investigations on single muscle fibres of rat and chicken have shown that the muscle membrane potential increases during ontogeny (Fudel‐Osipova and Marty‐nenko 1962, Boëthius and Knutsson 1966). This finding prompted a further interest in membrane characteristics associated with development and initiated the present study on the time relations of membrane potential build‐up throughout the cephalocauda

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04377.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Carlssonet al.(1963) and Kirshner (1962) have shown that ATP‐Mg stimulates uptake of amines in isolated adrenal medullary granules. This finding has been confirmed (Lishajko 1968) and in addition it was shown that ATP‐Mg inhibits the “spontaneous” release of amines when phosphate buffer was used as medium. On the other hand Okaet al.(1966), Poisner and Trifaro (1967) have reported that ATP‐Mg in certain incubation media increases the release rate of catecholamines in isolated chromaffin granules.In the present communication it will be shown that the releasing effect of ATP‐Mg is dependent on the presence of chloride ions in

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1969.tb04378.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY