摘要:

AbstractMechanisms underlying the plasma‐free fatty acids (FFA) lowering effect of angiotensin have been studied in anesthetized dogs. Angiotensin in pressor doses reduced fatty tissue blood flow (FBF) as well as plasma‐FFA. After ganglionic blockade, angiotensin had the opposite effects, as a slight increase was found in FBF and plasma‐FFA. Atropine or a β‐adrenergic blocking agent did not interfere with the angiotensin effect on plasma‐FFA. It is concluded that the angiotensin action on plasma FFA is secondary to its vasoconstrictive effect in adip

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05062.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractSensory messages about taste and temperature transmitted through single chorda tympani fibres have been studied by means of factor analysis using the varimax criterion for factor rotation. Our analysis indicate that all sensory qualities studied,i.e.varm, cold, salty, sour, sweet and bitter are conveyed to the brain as separate sensory modalities. No groups of interacting stimuli could be identified at the level of the primary afferent neuron. It seems particularly important that the pattern of neural activity elicited by gustatory qualities may change over time so that the dynamic properties of the transmission system emerges as a possible mechanism of sensory discrimination. Moreover, this time dependent shift in the input of information to the central nervous system may give a clue to the phenomenon of aftertaste.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05063.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractPGE1, PGE2and PGF2αin concentrations ranging from 3×10‐9M to 1.5 × 10‐6M were infused into the isolated perfused, sympathetically innervated rabbit heart in order to assess their capacity to inhibit the chronotropic, inotropic and noradrenaline overflow responses to sympathetic nerve stimulation, as well as the chronotropic and inotropic responses to infusion of noradrenaline. The coronary flow was increased by PGE1but not by PGE2of PGF2α. The three compounds did not change the heart rate or the contractile force, indicating that the reported increase in heart rate after i.v. infusion of PGE1or PGE2is reflex in origin. PGE1and PGE2inhibited the outflow of noradrenaline as well as the chronotropic and inotropic responses to nerve stimulation in a dose‐dependent way, while PGF2αwas ineffective. None of the compounds altered the chronotropic or inotropic response to exogenous noradrenaline. It is concluded that PGE1and PGE2but not PGF2α, inhibit the sympathetic neurotransmission in the rabbit heart, and that they do this mainly by reducing the release of the transmitter from the adrenergic nerv

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05064.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of inhibition of prostaglandin synthesis on the release of noradrenaline induced by sympathetic nerve stimulation was studied in the isolated perfused rabbit heart. It was found that 5,8,11,14‐eicosatetraynoic acid, a compound known to block prostaglandin synthesisin vitro, decreased the outflow of prostaglandins normally induced by nerve stimulation. Simultaneously the outflow of noradrenaline in response to nerve stimulation increased. Since the acetylenic acid did not affect the uptake of exogenous noradrenaline, the increased outflow probably reflects an augmented release of transmitter from the neurons. It has earlier been shown that exogenous prostaglandins inhibit the release of noradrenaline from adrenergic neurons, and that endogenous prostaglandin‐like substances are released in response to sympathetic nerve stimulation in amounts sufficient to exert this inhibitory action. Thus a prosta‐glandin‐mediated negative feed‐back control of the release of adrenergic transmitter is known to be feasible. The present observation that inhibition of prostaglandin synthesis enhances the release of noradrenaline, provides the first conclusive evidence for the occurrence of such an endogenous control

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05065.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe mechanism by which glucagon inhibits intestinal and vascular smooth muscle tone was studied in anesthetized cats. The intestinal motility was recorded by a volume recording device and the intestinal blood flow by connecting the left carotid artery via a drop recording unit with the superior mesenteric artery by a wide bore polyethylene tube. A femoral artery was used for recording of arterial pressure. Glucagon was administrated close intraarterially at different rates. In animals where the adrenals were left intact glucagoninfusion was followed by a considerable and immediate increase of intestinal blood flow and a somewhat delayed motility inhibition and blood pressure increase. When the adrenals were excluded glucagon still induced a blood flow increase. The motility inhibition and the blood pressure increase were both abolished, however. It is therefore suggested that glucagon exerts its action on the splanchnic area in two different ways, on the one hand by a direct effect on the vascular smooth muscles on the other hand by a release of catecholamines from the adrenal medullae which, in turn, inhibits intestinal smooth muscles.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05066.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractConscious rats were found to secrete saliva from the submaxillary gland when exposed to heat. In rats with sympathetically denervated glands the secretory rate was a little lower and in parasympathetically denervated glands the secretion was almost abolished. The salivary flow appeared to increase with increasing ambient temperature and the secretion started earlier at higher temperatures. The secretion elicited by heat stress was compared to the secretion evoked by electrical stimulation of the parasympathetic nerve to the gland. It is concluded that the salivary secretion evoked by heat stress is mainly mediated by the parasympathetic secretory nerves, although the sympathetic fibres also take part.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05067.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractIsotopically labelled noradrenaline (NA) exchange was determined in an improved preparation of NA storage vesicles isolated from bovine splenic nerve trunk. A Millipore filter technique was used which permitted analyses of unidirectional fluxes. In a Mg‐ATP supplemented medium at 30 and 20° C, vesicle NA is completely exchangeable with 0.5 to 3.0 μgl‐NA/ml in the medium. The kinetics are compatible with a single exponential component of exchange, and the data suggest a fully saturated Mg‐ATP complexing under these conditions.Reserpine in a concentration range between 2 × 10‐8and 2 × 10‐7M causes more pronounced inhibition of the transfer coefficient for NA influx than for efflux. However, no net loss of vesicle NA occurs because the drug inactivates a proportional amount of the readily exchangeable NA pool. Within the concentration ranges of NA and reserpine tested, virtually complete inhibition of NA exchange can be achieved and reversal of this inhibition by elevating the NA concentration in the medium can be demonstrated. The data is consistent with the suggestion that reserpine acts via transport sites in the vesicle membrane, rather than on the intravesicular NA complexper se.This membrane stabilizing concentration range of reserpine causes no obvious deleterious effects on the vesicles at the electron micr

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05068.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractExperiments by Bartonet al.(1968) and Hollenberget al.(1968) suggested that renal sodium excretion may be regulated by the distribution of blood flow within the kidney. Such a mechanism might account for the reduction in sodium excretion during lowering of arterial perfusion pressure, despite constant glomerular filtration rate and total renal blood flow (RBF). In the present study, renal blood flow in the outer half of the cortex (OCF) and inner half of the cortex (ICF), and in outer medulla (MBF), was examined during reductions of mean renal arterial pressure (RAP). RAP was reduced in steps by a clamp on the aorta or the renal artery, and at each pressure reduction OCF and ICF (cortex group, 7 dogs) and MBF (medulla group, 11 dogs) were measured by polarographic recording of hydrogen gas clearance with platinum electrodes inserted in the cortex, 2–3 mm and 6–7 mm respectively, and in outer medulla. RBF was measured by an electromagnetic flowmeter. At control pressure, OCF averaged 3.26 ml/min · g and ICF 3.45 ml/min · g, the difference between them being insignificant. An average decrease in RAP from 131 mm Hg to 76 mm Hg caused a 1% decrease in RBF and decreases in OCF and ICF to 89% (range 77–98%) and 87% (range 75–94%) respectively, both in per cent of control. The difference between OCF and ICF during clamping was not significant. At an average decrease in RAP from control of 126 mm Hg to 88 mm Hg, RBF decreased to 96% of control; MBF was not reduced (range 81–116%). The difference between changes in MBF and RBF was not significant. Atropinization did not change the pressure‐flow relationship of

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05069.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractEfferent impulses in the chorda tympani nerve of the rat could be recorded under neuroleptic analgesia but not under barbiturate anesthesia. The number of impulses recorded from the whole nerve ranged from 10 to about 120 imp/s. Recordings from branches of the combined chorda‐lingual nerve suggest that most of the observed activity was directed to structures inside the tongu

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05070.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe regulation of intracellular pH′ in the brain was studied in rats exposed to about 11% CO2for periods of 15 min to 72 h. At the end of each exposure period cisternal cerebrospinal fluid, as well as the supratentorial parts of the brain, were sampled and analysed for the CO2contents. The intracellular HCO3‐concentration was calculated assuming extracellular volumes of 12, 15 and 20%, respectively, and the intracellular pH′ was derived from the HCO3‐concentration and the mean tissue CO2tension. Acute hypercapnia (15 min) was associated with an increase in the intracellular HCO3‐concentration of about 6 meq/kg of i.e. water. With an extracellular volume of 15% the corresponding decrease in pH′iwas from 7.06 to 6.93. When the hypercapnia was upheld there was a further increase in the intracellular HCO3‐concentration of about 5 meq/kg and an increase in pH′ito about 7.03. Most, if not all, of this regulation of pH′ioccurred during the first 3 h. An analysis of the regulating mechanisms suggests that physicochemical buffering, metabolic consumption of acids, and transmembrane fluxes of H+or HCO3‐each contributed about a third of the total accumulation of bicarbonate in the cell

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb05071.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY