摘要:

AbstractThe effect of hypotonic mannitol and saline loading on the urinary diluting capacity in man has been examined. The further interpretation of the data was built on the assumption that the free water formation is determined by distal tubular Na+reabsorption. Thus it could be demonstrated that the distal tubular Na+reabsorption was at first enhanced and later suppressed by progressive increases in the total distal tubular Na+delivery. No relationship could be demonstrated between distal tubular Na+reabsorption and urinary Na+concentration. This was interpreted to mean that the distal tubular Na+reabsorption was independent of the transtubular Na+gradient.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04779.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractTapping on the cat's facial skin elicits two successive reflex discharges in the orbicularis oculi. The responses have similar thresholds and are most readily evoked from the skin overlying the muscle. Both discharges result also on tapping on a skin flap over the muscle, whereas tapping on the muscle belly is ineffective. Similar responses are elicited on electrical stimulation of low‐threshold trigeminal afferents; the central relay time indicates that the early response is mediated through a polysynaptic reflex arc. Stimulation of high‐threshold afferents in the facial nerve may give a long latency reflex response in the orbicularis oculi and facilitate transmission of a short‐latency reflex response in the same muscle set up by stimulation of trigeminal afferents. Recordings from peripheral filaments provide no evidence for the presence of afferent fibers from muscle spindles or other types of proprioceptors in the facial and trigeminal nerves. A twitch contraction of the orbicularis oculi elicits a high‐amplitude reflex response in the muscle through activation of trigeminal exteroceptive afferents; the possibility is considered that such afferents may serve a proprioceptive function in monitoring the degree of contraction of the facial

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04780.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractExtrahepatic elimination of galactose occurs mainly in the kidney. Urinary excretion as well as metabolic conversion may be of significance. At plasma concentrations of galactose between 60 and 1200 mg per liter in cats urine to plasma concentration ratios below one were never observed. At low filtered loads the reabsorption fraction was close to 1.0. At higher loads the reabsorption fraction decreased and seemed to converge towards 0.6. The rate of metabolic conversion of galactose in the kidney — calculated as the RBF times the arterio‐venous concentration difference minus the excretion rate — exceeded considerably the reabsorption rate at low filtered loads. At increasing loads the metabolic rates approached maximum values between 50 and 100 μg per minute and gram kidney weight. The capacity of the kidney for metabolic conversion of galactose appeared (per gram organ weight) to be in the same order of magnitude as that of the liver. Push‐flow experiments indicated that reabsorption of galactose takes place exclusively in the proximal tubular system. When, at low plasma concentrations, the metabolic rate exceeds the reabsorption rate the intracellular concentration of galactose in the tubular wall cells may stay low and this may promote diffusion into the cells and account for the high reabsorption fractions found (conversion reabsorption). At higher concentrations, where the reabsorption rate exceeds the metabolic rate, reabsorption is probably due increasingly to carrier‐facilitated transcellular bac

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04781.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe contractions of the seminal vesicle in response to hypogastric nerve stimulation or coaxial stimulation were recorded with a balloon inserted in the lumen of the seminal vesicle.Adrenaline (A), noradrenaline (NA), acetylcholine (Ach), histamine (Hi), serotonin (5‐HT), barium chloride and high concentrations of angiotensin were found to potentiate the motor response of the seminal vesicle to sympathetic nerve stimulation. This potentiation occurred with concentrations 10–100 times smaller than those giving a direct contraction of the organ. Prostaglandins (PGE1, PGE2and PGF2a) in low concentrations (1–10 ng/ml) exerted no effect or caused a slight decrease in the response to sympathetic nerve stimulation, while higher concentrations (100 ng–1 μg/ml) enhanced the response to nerve stimulation. This effect was pronounced with PGE1, but rather weak with the other prostaglandins. Oxytocin, vasopressin and felypressin were without effect on the seminal vesicle preparation. It is concluded that the seminal vesicle responds to smooth muscle stimulants in a similar way as the vas

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04782.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractSingle unit impulses were recorded from the median and the ulnar nerves in waking human subjects with percutaneously inserted tungsten electrodes. 61 mechanoreceptor units in the glabrous skin were analysed with regard to the characteristics of their receptive fields and the basic physiological properties of their endings. 4 different types of receptors could be distinguished. This distinction was based mainly upon the adaptation and the receptive field characteristics although other differences were also observed. The fields had very sharp borders for the majority of the slowly as well as the rapidly adapting units. The field sizes varied considerably: between 10 mm2and 600 mm2. For a minority of the receptors, slowly as well as rapidly adapting ones, the receptive fields were constituted of a center of high sensitivity and a wide surrounding area of lower sensitivity without distinct borders. The four types of receptors encountered in the present study have striking similarities with four different types of mechano‐receptors which have been described in sub‐human primates, namely the type I and type II slowly adapting, intradermal receptor, according to Iggo's terminology, an intradermal rapidly adapting receptor and the Pacinian corpuscle which is located in the subcutaneous tissues. Roughly 75% of the units were slowly adapting. This is a much larger proportion than found in the monkey. Further, it was shown how the recording method offers the opportunity to analyse the perceptive responses as well as the neurophysiological responses in first order neurons to mechanical stim

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04783.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractEvoked focal potentials from the contralateral fore‐ and hindlimb interosseous nerves Int.f. and Int.h. as well as from Pacinian afferents were recorded in sensorimotor cortex and in S II in cats anaesthetized with chloralose. Low threshold, short latency potentials from Int.f. were evoked in the lateral sigmoid gyrus, in the region of the post cruciate dimple, in the rostral bank of the lateral ansate sulcus, in the lower bank of the anterior suprasylvian sulcus and in S II. The shortest latencies varied between 5.0–6.0 msec. Mechanical stimulation of dissected clusters of Pacinian receptors in the interosseous region evoked cortical responses in the same areas with slightly longer latencies. Low threshold electrical stimulation of Int.h. afferents evoked in addition to the known projection to S II (McIntyre 1962) initially positive potentials in two loci of the postsigmoid gyrus, one on the dorsal, the other on the medial aspect of the hemisphere. The latencies in these loci were as short as those in S II. i.e. 9.5–10.0 msec. Zonal convergence between projections from interosseous and Group I muscle afferents was observed. The Int.f. path ascends in the dorsal column. A cortical potential was however, evoked in the postsigmoid gyrus by electrical stimulation of high threshold Int.h. afferents after transection of the dorsal columns at cervical

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04784.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe relationship between the release of histamine and35S‐labelled heparin from mast cells exposed to compound 48/80in vitrohas been studied in order to elucidate the mechanism of histamine release induced. The cells were taken from rats injected 3, 6, 12 or 20 days earlier with Na235SO4. A good correlation was found between the two release curves. From studies of the35S/protein ratio in the extruded granules and granules obtained by water lysis of the washed compound 48/80‐treated cells it appears that the35S‐labelled heparin was first evenly distributed with respect to the granule protein 12 to 20 days after injection. Using cells taken after such an interval the ratio percentage histamine release/percentage35S release was found to be 1.1–1.4. We conclude from these results and from the similarity between the time courses of histamine and35S release that the mechanism of histamine release induced by compound 48/80 involves an initial extrusion of histamine‐cotnaining granules, followed by an exchange of histamine in the extruded granules and cations in the extracellul

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04785.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractMale albino mice were injected intraperitoneally or intravenously with14C‐labelled nicotine. Both untreated and phenobarbital pretreated mice were used. The concentrations of nicotine and metabolically formed cotinine were determined in the brain, liver and blood 1, 2.5, 5, 10, 20 and 60 min after injection. It was found that phenobarbital pretreated mice exhibited an enhanced liver metabolism of nicotine both in vitro and in vivo. The increased liver metabolism caused a significant decrease of nicotine concentration in the brain only when nicotine was given intraperitoneally. Phenobarbital pretreatment elevated the intraperitoneal LD50value 2–3 times and also increased tolerance to repeated sublethal doses of nicotine. No change in the intravenous LD50value was obser

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04786.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe effects of volatile anesthetics (nitrous oxide, halothane, diethyl ether and cyclopropane), of Fentanyl, and of barbiturates (thiopentone, phenobarbital and amobarbital) on labile phosphates and on intra‐ and extracellular lactate, pyruvate and bicarbonate concentrations of brain tissue were investigated in rats, which were immobilized and artificially ventilated so as to give arterial CO2tensions of 35–40 mm Hg. It was found that the type or the depth of anesthesia did not significantly influence the tissue concentrations of phosphocreatine, ATP, ADP or AMP. There were very small differences in the tissue lactate concentration in the nonbarbiturate groups, and thus no indication that the lactate concentration varied with the depth of anesthesia. However, in all barbiturate groups there was a lowering of the lactate concentration and an increase in the intracellular pH'. In contrast to the volatile anesthetics the barbiturates gave significant decreases also in the calculated cytoplasmatic NADH/NAD+ratio. The experiments thus failed to indicate that anesthetics inhibit electron transport or energy transfer reactions in the brain, at least under the conditions studied. In addition, they suggest that barbiturates, including, amobarbital, shift the balance between energy‐yielding and energy‐requiring reactions in favour of an oxidate

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04787.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Abstract20 pigs weighing 21–124 kg were used to determine the clearance of PAH, N4‐acetylated PAH and PAHtotal, and for determination of acetylation of PAH and de‐acetylation of N4‐acetylated PAH in the kidney. By examining blood samples taken from a. renalis and v. renalis and urine collected simultaneously, the acetylation and de‐acetylation of PAH and N4‐acetylated PAH in the kidney were determined on 9 pigs. 6 of these acetylated PAH (1.5–10 per cent), while 3 de‐acetylated N4‐acetylated PAH (2–21 per cent). The extraction percentage for PAH and N4‐acetylated PAH were 91 ± 1.4 (S.E.M.) and 84 ± 2.1 respectively. The ratio between clearance of N4‐acetylated PAH and PAH was found to be 1.08 ± 0.07 and between clearance for P

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1970.tb04788.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY