摘要:

AbstractA comparison was carried out between direct and indirect measurements of blood flow in follicular ovaries of anaesthetized laparotomized rabbits: Direct measurements by timed quantitative sampling of ovarian venous blood yielded blood flow values 3 times higher than those found with the use of 15 μm radioactive microspheres. However, when simulating the surgical trauma associated with direct measurements, the microsphere technique gave the same high ovarian flow values, indicating that this type of trauma caused ovarian hyperemia. It is concluded that direct measurements of blood flow, as performed in the present study, are unsuitable for investigations of circulatory events in the ovary. Mechanically induced ovarian vasodilatation is probably a factor which helps to explain the diverging data on blood flow obtained with direct and indirect methods. The radioactive microsphere technique appears to provide a means for reasonably reliable ovarian blood flow measurements in laboratory animals

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05855.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractDuring pulmonary microembolism subsequent to induced platelet aggregationin vivo, a pressor response is elicited in the lungs due to the release of vasoactive substances. During the perfusion of isolated cat lungs with whole blood, platelet aggregation induced by collagen released prostaglandin‐like substances (PG‐LS), and a rabbit aorta contracting substance (RCS) as measured by continuous bioassay of the venous effluent. This release occurred in parallel to the pulmonary pressor response. The same amount of PG‐LS and RCS was released when the lungs were replaced by a blood filter to trap platelet aggregates. Apparently PG‐LS and RCS are released from platelets during their aggregation. As E‐ and F‐type PGs are rapidly inactivated in the pulmonary circulation, there must either be an equal generation of PGs in the lungs themselves, or rather, the release of PGs from platelets must occur distal to the inactivation mechanism without any additional PG‐release from the lungs. The exact role of PGs in the lung responses to intravascular platelet aggregation

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05856.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe effect of transient anoxia on the cochlear microphonic potential at different sound frequencies was investigated. The microphonic potential was recorded with glass microelectrodes in theductus cochlearisof the pigeon ear. Transient anoxia had different effects, related to frequency, on the amplitude and the relative phase angle of the microphonic potential recorded from one place in theductus cochlearis.At frequencies equal to and higher than the best frequency the amplitude of the microphonic potential was more sensitive to anoxia than it was at lower frequencies. Microphonic potential at 1 kHz lower than the best frequency was often enlarged in amplitude during transient anoxia. The results suggest that this frequency‐dependent effect is a positional one. Changes in the phase were largest around the best frequency. It is inferred that anoxia causes complex changes in the pattern of vibration in the cochlear partition. The observed changes in amplitude and also changes in phase are caused by the combined effects of reduction of the endolymphatic potential and changes in vibration patter

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05857.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractNet transcapillary fluid exchange in skin tissue (paw) and small intestine was observed during a 90 min period of hemorrhagic hypotension at 50 mm Hg in the cat. Reflex fluid transfer was prevented by regional sympathectomy and α‐adrenergic blockade. Early in hemorrhage, fluid absorption from the extravascular space occurred in both tissues, apparently caused by osmosis. The process was thus co‐ordinated in time with a positive arterio‐venous osmolar difference, in turn caused by a marked arterial hyperosmolality. Experimental arterial hyperosmolality of similar magnitude, created by i.v. infusion of hypertonic glucose in non‐bled animals, led to transcapillary fluid absorption in both intestine and skin and at rates similar to those in bleeding. Regional hypotsionenper secaused no fluid absorption. Later in hemorrhage (>30 min), plasma fluid moved into the extravascular space both in skin and intestine, apparently due to a gradual increase of capillary hydrostatic pressure. It is concluded that the arterial hyperosmolality during bleeding can cause transcapillary fluid absorption in intestinal and skin tissues, as previously shown for skeletal muscle (Järhult 1973). The hemodynamic significance of this process for plasma volume regulation in hemorrhage is, however, much greater in skeletal muscle than in intestine and skin, mainly due to the much larger total mass of the musc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05858.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe autonomic innervation of the rat urinary bladder was studied using histochemical methods and nerve stimulations. A sparse adrenergic innervation of the detrusor muscle was found. It was supposed to originate from long adrenergic neurones. The trigonum area had a rich supply of adrenergic fibres, probably derived from short adrenergic neurones. A uniformly rich supply of acetylcholine‐esterase (AChE)‐positive nerves was found in the whole bladder. Postganglionic sympathetic denervation caused no detectable change of adrenergic or AChE‐positive nerves in the bladder, while parasympathetic decentralization or denervation produced a total disappearance of adrenergic fibres. The AChE‐positive nerves were appreciably reduced in number after parasympathetic decentralization and not detectable after postganglionic denervation. Neither adrenergic nor AChE‐positive ganglion cells could be demonstrated in the bladder wall. Electrical stimulation of the hypogastric nerves or the pelvic nerves distal to the pelvic ganglia elicited contraction of the detrusor muscle. The responses were not affected by hexamethonium, dihydroergotamine or propranolol but were slightly reduced by guanethidine, reduced to about 40% by atropine and potentiated by eserine. Stimulation of the pelvic nerve proximal to the pelvic ganglion was partially blocked by hexamethonium. It is concluded that the urinary bladder of the rat is supplied by postganglionic adrenergic fibres mainlyviathe pelvic nerves and only to a lesser extentviathe hypogastric nerves. Probably cholinergic fibres pass to the bladder mainlyviathe pelvic nerves but alsoviathe hypogastric nerves, having their cellbodies outside the bladder wall, partly proximal to the pelvi

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05859.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe effects of ATP, ADP, AMP and adenosine were studied on the spontaneous mechanical activity of the rat portal vein. It was found that ATP and ADP, in concentrations higher than 300 μM, caused a transient tetanus, followed by inhibition, and at lower concentrations an increase in the frequency and amplitude of the spontaneous contractions. AMP and adenosine on the other hand, inhibited spontaneous activity, by reducing the amplitude of contractions and increasing their frequency. The effects were dose‐dependent. ATP was found to be 2.2 times more potent than ADP, while AMP and adenosine were equipotent. Weak inhibitory effects were obtained with GMP, guanosine and adenine, while GTP, 3′5′‐cyclic AMP and guanine had no effect. ATP and ADP increased the K‐contracture, while AMP and adenosine relaxed it. The effects of ATP were augmented in Mg‐free solutions and partially inhibited in Mg‐high solutions in the normally polarized muscle, while Mg had no influence on the ATP‐induced contraction in the depolarized muscle. Theophylline potentiated the inhibitory response to AMP and adenosine. Adrenergic and cholinergic blockers had no influence on the response to ATP, ADP, AMP or adenosine. It is suggested that the effects of ATP and ADP are linked with Ca++movements across the membrane, while AMP and adenosine might stimulate intracellular metabolism causing increased intracell

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05860.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe incorporation of labelled phospholipid precursors, [Me‐14C]‐choline, L‐[3‐14C]‐serine, [2‐14C]‐ethanol‐amine and [2‐3H]‐myoinositol into the phospholipids of isolated rat mast cells was studies. The label from the different precursors were found to be essentially associated with compounds with the t.l.c.‐motility of the respective phospholipids. Whereas the incorporation of [Me‐14C]‐choline and L‐[3‐14C]‐serine showed evidence of saturation, the incorporation of [2‐14C]‐ethanolamine was linear with time (2 h) and it was not saturated by increasing the concentration from 0.07 mM to 2.07 mM. The incorporation of [2‐3H]‐myoinositol was stimulated by Ca2+(1 mM) or Mg2+(1 mM), while the incorporation of the other precursors was stimulated only in the presence of both Ca2+and Mg2+(1 mM). Antimycin A (1 μM), an inhibitor of the respiratory chain, significantly inhibited the incorporation of [Me‐14C]‐choline, L‐[3‐14C]‐serine and [2‐3H]‐myoinositol but not that of [2‐14C]‐ethanolamine. The experimental system used might be a useful model for studies on the

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05861.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe subcellular localization of histamine was studied in sensitized rat mast cells following antigen challenge and in granules obtained from sonicated cells, using an electron microscope autoradiographic technique. The mast cells were furnished with labelled histamine by incubation in3H‐histidine. The silver grain distribution (reflecting the localization of radioactive histamine) was highly non‐random. The highest silver grain densities occurred over homogeneous, electron dense (normal) granules and moderately electron dense granules. Swollen, less electron dense (“changed”) granules with a reticular appearance and devoid of a limiting membrane had the lowest density of all subcellular structures studied and were therefore probably almost free of histamine. There was a good correlation between the percentage of electron dense granules, the histamine content and the silver grain density in saline‐washed granule fractions isolated after sonication of mast cells for different times. These results support the hypothesis that histamine release occurs during the sequential exocytosis of storage granules, and during the sonication of mast cells, probably as a cation exchange between the amine, which is ionically bound to the heparin‐protein complex of the granule matrix, and cations from the extracellular fluid. The exchange will occur as soon as the perigranular membrane becomes permeable to water

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05862.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

It was investigated whether there is an endogenous factor in the brain which binds to the opiate receptor in neural tissue. Extracts from rat brain were processed in different ways; fractions were assayed for ability to inhibit the receptor binding of dihydromorphine. There was no evidence for high‐molecular weight substances or lipid soluble substances with such ability. On the other hand, processing of an acid water extract of brain except the cerebellum (which was negative) yielded an active fraction with receptor blocking activity. This fraction was heat stable, polyionic and had an apparent molecular weight of 1000–1200 dalton. These and other characteristics indicate that it might well be a peptide. The factor inhibited binding to the opiate receptor in synaptic plasma membranes of rat brain and to the receptor of the guineapig ileum although it was less effective on the latter, particularly after long‐term incubation. The interaction between the factor and dihydromorphine was reversible and apparently compet

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05863.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

AbstractThe fastigial influence on intestinal motility was investigated in acute experiments on chloralosed casts. Motility was recorded both from the small and large intestine. Electrical stimulation of the rostral fastigial pole produced, in combination with a blood pressure rise, increased motor activity in ileum and colon while jejunum could respond with either increased or decreased mobility. The intestinal responses were neither secondary to changes in intestinal blood flow, nor to baroreceptor reflexes induced by the increased blood pressure. The excitatory responses were not due to increased parasympathetic activity since sectioning of such pathways failed to abolish the responses. Insted, interruption of adrenergic sympathetic discharge, accomplished either by guanethidine or by sectioning of relevant nerves, did eliminate the responses, indicating that the fastigial effects were mediated by suppression of prevailing adrenergic tone. Noxious stimuli to the abdomen, including laparotomy, inhibit intestinal motility by a reflex increase in adrenergic discharge. It is suggested that fastigial influence on intestinal motility is mainly due to suppression of this reflex.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1975.tb05864.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY