摘要:

6‐hydroxydopamine (6‐OHDA), 15 or 50 mg kg‐lgiven as bolus i.v. injection to adult conscious rats with aortic catheter, rapidly increased mean arterial pressure by 70–78 mmHg. The pressure returned to normal within 4060 min. The cerebrovascular permeability in rats given 6‐OHDA and sacrificed 10 or 60 min later was enhanced as indicated by extravasation of Evans blue albumin and significant increase of125I human serum albumin content in brain tissue compared to control rats. When the increase in blood pressure was diminished by i.v. phentolamine, 6‐OHDA treated rats did not differ from controls. It is concluded that the blood pressure elevation induced by i.v. 6‐OHDA facilitates the entry of the drug into the bra

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06622.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Morphology and function of the adrenergic innervation of the liver were studied in cats. Fluorescence microscopy revealed a dense network of adrenergic nerve fibres in association with interlobular vessels and a sparse, but unequivocal innervation of the hepatocytes. These parenchymal adrenergic nerve fibres were more frequent in kittens (2 months old) than in adult cats. Electrical stimulation of the hepatic sympathetic nerves in the adult adrenalectomized cat evoked a small but insignificant increment (1–2 mM) of arterial plasma glucose concentration. When both hepatic and pancreatic sympathetic nerves were stimulated simultaneously, arterial plasma glucose concentration increased significantly by about 6 mM. We conclude that the pronounced hyperglycemic effect of activation of the sympathetic nervous system in the cat is mediated mainly via an adrenergic influence on the release of insulin and glucgon from the pancreas. The sympathetic innervation of the cat liver parenchyma seems to contribute to the hyperglycemia to a minor extent onl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06623.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The effect of chronic nicotine treatment, given in the drinking water for 8–10 weeks in a dose equivalent to that of a heavy cigarette smoker, and of withdrawal 2 days on acetylcholine (ACh), choline acetyltransferase (CAT) and ACh‐esterase (AChE) activities in the preganglionic cervical nerve and the superior cervical ganglia (SCG) of rats, were studied. Control rats were housed and handled as the nicotine rats. After cutting the preganglionic nerve 7–19 h before dissection, ACh, CAT and AChE accumulated in the nerve part proximal to the cut (relative to the nerve cell bodies in the spinal cord). A clearance of these substances was observed in the nerve distal to the cut. This indicates that all 3 substances are transported proximo‐distally in this preganglionic cholinergic nerve. In the SCG, ACh was decreased already by 7 h (to about 60%), while CAT and AChE‐activities were lowered to 60% and 80%, respectively, at 19 h after cutting the nerve. Chronic nicotine treatment caused an increased ACh accumulation (by about 35 %) and a decreased CAT accumulation (by about 20%) in the cut nerve, while the ganglionic levels of all 3 substances were essentially unchanged. Withdrawal of nicotine for 2 days prior to the final experiments caused a reduced ACh‐accumulation (by about 30%) in the nerve and normalized the CAT accumulation. The AChE‐activity of intact nerve was markedly increased to about 175% of control, and the transportable fraction of AChE (clearance distal to the cut) was about twice as large as in control. In the SCG withdrawal caused marked changes in the ACh content, which was decreased to 62% of control. CAT‐activity was increased to 117% of control while AChE was unchanged. Our hypothesis to explain the results is that chronic nicotine treatment and in particular withdrawal of nicotine may cause marked alterations in the activity of the preganglionic neuron. This may induce changes in the intra‐axonal transport of the 3 substances and an increased turnover of ACh in the nerve terminals of the SCG after withd

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06624.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The rat urinary bladder was deprived of half of its innervation by removing the pelvic ganglion on one side. The motor responses of such a partially denervated bladder to stimulation of the pelvic nerve on the other side were examined I week, 1 month and 2 months postoperatively. On all three occasions the increase in pressure of the operated bladder was larger than that of the control bladder; the enlargement was most marked 2 months after operation. The responses were further enlarged by esenne, and markedly reduced by atropine. The present results combined with those of previous investigations, showing a rapid recovery in the activity of the acetylcholine forming enzyme from a reduced level and a transient supersensitivity to chemical stimuli after unilateral removal of the pelvic ganglion. suggest that the enlarged responses to nerve stimulation 1 week postoperatively are mainly due to sensitization, while those observed at the later stages are due to collateral sprouting from the cholinergic nerve fibres of the intact pelvic nerve.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06625.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Nerves containing vasoactive intestinal peptide (VIP) were observed in salivary glands of rat, cat and man. VIP nerves were numerous in the cat while they were moderate in number in rat and man. The measured concentrations of immunoassayable VIP were in agreement with the immunohistochemical findings. Electrical stimulation of the feline chorda lingual nerve, which stimulates salivary secretion and local blood flow, resulted in a marked elevation of VIP in the venous effluent from the submandibular gland. VIP was not measurable in saliva. Gel permeation chromatography of extracts from cat submandibular gland and from venous plasma collected before and during nervous stimulation revealed one immunoreactive peak with an elution position identical to that of highly purified porcine VIP. The finding of neuronal VIP in salivary glands, its release upon nerve stimulation and its known effect on local blood flow support the view that VIP is a neurotransmitter in the salivary glands.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06626.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The distribution kinetics of ethanol in the isolated perfused rat liver at various flow rates and ethanol concentrations were studied by the indicator diffusion technique using11C‐labelled ethanol. A double tracer solution with99mTc‐labelled red blood cells as the vascular reference and11C‐ethanol as the test substance was injected into the catheter connected to the portal vein. Time‐activity curves were monitored by a Nal(T1) scintillation detector above the outflow catheter. The following values were obtained: 0.95±0.01 for the maximal extraction (Emax), 3.0±0. 1xflow (r=0.98) for the capillary permeability surface area product (PScap), 18.7±12.5% for the vascular volume (V1) and 56.2±9.0% for the ethanol distribution volume (V2). The volumes were calculated from the products of mean transit time (MTT) and flow (f), and PScapwas calculated from the equation PScap=‐fxIn(l‐Emax). The results show that the ethanol distribution in the liver is flow limited since Emax, was constant at various flow rates (0.67–2.55 ml/gxmin‐1). The distribution volumes obtained agree well with the values for liver vascular volume and water distribution volume reporte

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06627.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The cardiac chronotropic effects of distension of pulmonary vein‐left atrial junction were investigated in conscious dogs and in dogs anesthetized with intravenous alpha‐chloralose (100 mg/kg) or pentobarbital (30 mg/kg). All the experiments were made on trained, chronically instrumented, closed chest animals held in horizontal position. Inflation of a single small balloon in the junction elicited a tachycardic response both in conscious and chloralose‐anesthetized dogs, while in pentobarbital anesthesia no change in heart rate was found. Contrary to reports of other investigators, no transient bradycardia was found, nor any correlation between predistension heart rate and the increase in heart rate due to the distension. It is suggested that the choice of anesthetic can be done only after its modifying effect on the parameter studied is known. Only the use of trained, chronically instrumented and conscious dogs will reveal this e

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06628.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The EDTA space and the plasma water volume of the whole animal and selected tissues were investigated with constant EDTA infusions of different duration in the rat. The calculated EDTA space increased with the duration of the infusion both in the whole animal and the tissues sampled. The plasma water volume remained constant. and therefore the calculated increase of the EDTA space suggests a slow intracellular accumulation of the tracer. As intracellular accumulation of EDTA increases with experimental time, it is necessary to use as short an experimental interval as possible to reduce this error when determining extracellular fluid volumes.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06629.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The contracture elicited in the rat portal vein by hyperosmotic solutions (HC) has been investigated with respect to its Mg2+‐dependence and its mechanical properties. Comparison was made with K+‐induced contractures (KC) of similar force. In contrast to its relative resistance to Ca2+‐depletion, HC is entirely abolished after depletion of both Ca2+and Mg2+ions. After readdition of Mg2+alone, HC can be partially restored again. Isotonic quick release expts were performed on muscles in HC, KC and after passive stretch (PS) to a similar total tension and the length responses following the releases were analyzed. The immediate elastic response showed that stiffness was markedly higher in HC than in KC. whereas in PS it was much lower. After the elastic response a quickly decaying exponential component could be distinguished from the later more steady length change. The time constant of this transient response was 40–50 ms (KC) or 25–30 ms (HC). On release to a minimal afterload the amplitude of the transient response was about 1 % (KC) or 0.5 % (HC) of the initial muscle length, decreasing with increasing afterload. A corresponding transient lengthening response was seen after a step to a force greater than the isometric tension. Transient length responses in PS were much smaller than in KC or HC following force steps producing similar elastic recoils. The late shortening in HC and KC, interpreted as the isotonic response of the contractile system, could be fitted to Hill's eq. Vmaxin KC ([Ca2+]=0.5 mM) was 0. 25times;0.02 and in HC 0.05×0.01 (SE,n=6) lengths/s. The results of this investigation support the conclusion that HC originates in the contractile system of the muscle. The quantitative differences in mechanical properties are discussed against possible alterations in HC of cross‐bridge behaviour and/or filame

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06630.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The contracture induced by hyperosmolality (HC) in the rat portal vein has been investigated with respect to its metabolic properties. Oxygen consumption (Jo2) and lactate production (JLA) were measured. Comparison was made with K+‐induced contractures (KC). Variation in active force was produced for both kinds of contracture by alteration of muscle length. Measurements were also made in normal isotonic solution, where the muscle is spontaneously active, and in Ca2+‐free isotonic solution. At short muscle lengths, where no active tension was produced, Jo2was lower in HC than in KC. In contrast, JLAwas greatly enhanced in HC, so that calculated ATP turnover (Jatp) was almost the same in both kinds of solution. Comparison of metabolic rates at long and short muscle length and correlation to force development allowed calculation of tension‐dependent metabolism. In normal solution (spontaneous activity) tension‐dependent metabolic rate was much greater than in either kind of contracture. No difference in tension‐dependent Jo2, Jlaor JATPcould be detected between HC and KC. In nominally Ca2+‐free solution, force development and metabolic rates in HC did not differ from those in Ca2+‐containing solution. Glucose removal abolished lactate formation in HC. The temporal variations of Jo2and active force during 30 min of HC and KC were followed. In HC, force development increased with time, whereas in KC it decreased. Tension‐independent Jo2declined with time in HC but stayed constant in KC. On the other hand, tension‐dependent Jo2was unchanged in HC but declined in KC. The results of this study indicate that despite alterations in overall cell metabolism caused by the hypertonic solution, the energetic aspects of cross‐bridge operation may be similar in HC and KC, despite prominent differences in dynamic me

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1980.tb06631.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY