摘要:

AbstractRat mast cells were incubated with14C‐5‐hydroxytryptamine (5‐HT),14C‐dopamine (DA),14C‐noradrenaline (NA) or14C‐histamine (Hi). The influence of amine concentrations, temperature and metabolic inhibitors indicate that carrier‐mediated transport mechanisms are involved in the uptake of the amines. Chlorpromazine (CPZ) in concentrations of 0.1–10 μM inhibited the uptake of 5‐HT, DA and NA competitively and reduced the uptake of Hi. Ca++ decreased the effects of CPZ. The results suggest that Ca++ may play an important part in the mechanis

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSlices of kidney cortex and liver, pieces of lateral choroid plexus and of ciliary body with or without iris were incubated in a potassium‐rich medium containing labelled iodipamide often together with labelled o‐iodohippurate. Tissues were from rabbits, guinea‐pigs, monkeys (3 species), dogs, cats and chicken. Iodipamide at 0.5—2 μM depresses uptake of labelled iodipamide by rabbit kidney cortex wthout affecting uptake of o‐iodohippurate. Hippurate at 30 mM suppresses uptake of o‐iodohippurate in all tissues tested but leaves a fraction of iodipamide uptake in all tissues and species tested. The findings with o‐iodohippurate uptake are compatible with a single uptake system, the findings with iodipamide and the kinetics derived for this substance are incompatible with a single uptake system. Iodipamide seems to be accumulated by one hippurate‐sensitive system shared with o‐iodohippurate and at least one other, hippurate‐insensitive system. This latter system usually is a minority system in kidney cortex and anterior uvea but dominates in liver and choroid plexus and in cat kidney cortex. The hippurate‐insensitive system can be suppressed by probenecid but needs a higher concentration than the h

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe sodium pool of frog skin was studied by a method of continuous direct analysis under open‐ and short‐circuit conditions. No change in the transport pool on short‐circuiting was found. The results are discussed on the basis of proposed models for the sodium transport in frog

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractTwo distinctly different renal functional states were obtained in parallel series of non‐diuretic rats anesthetized with Amytal and Inactin, respectively.In the Amytal series proximal reabsorption rates ranged from 0.34 to 1.19 ml.min‐1· g KW‐1(mean value 0.72 ml.min‐1· g KW‐1). The reciprocal of the occlusion time (1/OT) and of transit time (1/TT) increased in direct proportion to the inulin clearance (ClIN) indicating that proximal luminal diameter remained unchanged over the “spontaneous” range of values. Proximal as well as distal reabsorption rates were independent of serum‐ and tissue Amytal concentrations while proximal reabsorption rate was inversely correlated with log renin activity of serum.In the Inactin‐series proximal reabsorption rate was depressed and ranged from 0.20 to 0.74 ml.min‐1· g KW‐1(mean value 0.46 ml.min‐1· g KW‐1). 1/OT and 1/TT was constant indicating a direct relationship between luminal diameter and ClIN. Proximal reabsorption rate was inversely correlated with serum Inactin concentration, while no relationship between proximal reabsorption rate and log renin activity was apparent.It is concluded that the variation in proximal reabsorption rate (and filtration rate) observed in Inactin anesthetized rats is induced by the anesthetic which in some way limits the reabsorption rate. The variation observed in Amytal anesthetized rats, on the other hand, is “spontaneous”,i.e. the rate is limited by

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe effects on transmission in the Ia inhibitory pathway to motoneurones by volleys in ipsilateral primary afferents were investigated with intracellular recording from motoneurones. In spinal cats under chloralose anesthesia Ia IPSPs in flexor as well as extensor motoneurones were regularly facilitated by volleys in cutaneous, high threshold muscle and joint afferents. In decerebrate cats with a low pontine lesion IPSPs were not facilitated from high threshold muscle and joint afferents, although volleys in low threshold cutaneous afferents evoked a facilitation also in this preparation. It is postulated that the Ia inhibitory interneurones receive excitatory actions from the ipsilateral flexor reflex afferents (transmission depressed in the decerebrate state) and through a separate pathway from low threshold cutaneous afferents. The recurrent effects from motor axon collaterals were investigated on inhibitory transmission to motoneurones from different afferents. A strong positive correlation was revealed between recurrent depression of IPSPs evoked from different afferents and facilitation of Ia IPSPs by the same afferent volleys. This suggests that the recurrent depression of IPSPs from different primary afferents depends on an excitatory convergence from them onto the Ia inhibitory inter‐neurones, which mediate at least part of the IPSP evoked in the motoneurone from these afferent

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe isolated cat gastrocnemius preparation was used to study shunting by diffusion of133Xenon from arterial to venous blood.133Xenon in saline,51Chromium‐labelled erythrocytes, and T1824‐albumin were mixed and injected as a bolus into a side branch of the femoral artery. The muscle was autoperfused and stimulated electrically. Gas tight samples were taken every 0.7 to 1.0 s with a special technique developed for this purpose. The effluent blood from the muscle was collected in a 1.5 m long glass tube (i.d. 2 to 3 mm), and from a side branch at the inflow end of the tube mercury drops were led into the tube dividing the blood stream into samples. The inflow was stopped after 20 seconds and the contents of the two isotopes in the samples were measured by collimated counting externally over the tube. The T1824‐analysis were performed spectrophotometrically.133Xenon appeared in the venous samples before the intravascular reference tracers indicating that133Xenon was shunted by diffusion from arterial to venous blood. The fraction of133Xenon shunted by diffusion was estimated to about 11 per

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00226.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe relationship between the length and stiffness (force/length change) of active muscle and the rates at which motor units are activated by distributed stimulation of divided ventral rootlets supplying the muscle has been explored in cat soleus and lateral gastrocnemius. At stimulus rates equivalent to those used in locomotion (15—55 p/s) peak muscle stiffness is at muscle lengths also used in locomotion. At lower rates of stimulation equivalent to those developed in the tonic stretch reflex of the decerebrate cat, peak muscle stiffness occurs at larger muscle lengths but these lengths are within the range of those used for investigation of the reflex. These experimental results were then compared to the sets of theoretically derived results concerning: a) the amount of force needed from the ankle extensors to counteract a load applied to the hindlimb along a vertical axis when ankle and metatarsophalangeal angles are changed relative to the mechanical axis; and b) the amount of force developed by ankle extensors during slow walking. In all cases (theoretical and experimental) the results reveal a close correlation between required force, muscle length and muscle stiffness. The time lag between a change in motor unit discharge and tension development was also calculated to reveal that in many situations (notably gallop) only muscle stiffness can provide a load compensation, whereas the delays are too long to allow a reflexly induced load compensatio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00227.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe histochemically demonstrable catecholamines of newborn rat carotid bodies were studied using the formaldehyde induced fluorescence (FIF) method. The effects of both heavy anoxia and repeated injections by glucocorticoids were registered. The newborn rat carotid body consisted of bright yellow fluorescing cells. During the following 2 weeks the intensity of this fluorescence decreased distinctly while fluorescent network of adrenergic nerve fibres developed. The fluorescent nerves were in close contact with the chief cells of the carotid body. Hydro‐cortisone or prednisolone treatment prevented the loss of fluorescence normally occurring. Anoxia caused a marked decrease in the FIF in the majority of glomus cells in 9—16 day old r

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00228.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractIt has been found recently that the dog's parotid is supplied with postganglionic secretory fibres which travel not only in the auriculo‐temporal nerve but also outside this nerve in the adventitia of the internal maxillary artery. In the present experiments acetylcholine was found to appear in the perfusate from the gland when the auriculo‐temporal nerve was stimulated. When both this nerve and the fibres on the internal maxillary artery were excited, the yield of acetylcholine was doubled. It is concluded that the auriculo‐temporal nerve and the nerves on the internal maxillary artery contain cholinergic nerves in about equal am

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00229.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractRecently earlier unknown secretory nerve fibres to the parotid of the dog have been traced outside the auriculo‐temporal nerve, on the internal maxillary artery and in the facial nerve. In the present experiments it was investigated whether they conveyed impulses from the “classical” preganglionic nerve, the tympani one, or from secretory nerves outside this nerve, the existence of which has been suggested by previous workers. The parotid secretory response to electrical stimulation of the tympanic nerve was found to be successively reduced when the auriculo‐temporal nerve, the internal maxillary artery and the facial nerve were divided. Some additional evidence is presented for the conception, that most of the impulses travel in the tympanic nerve and are conveyed to the gland via the auriculo‐temporal nerve and the adventitia of the internal maxillary artery. Uncharted secretory pathways outside the tympanic nerve were found to contribute very little to the reflexly induced secretory response, because after division of the tympanic nerve this response was abolished in 5 glands out of 10, whereas only a slight secretion was obtained in t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1972.tb00230.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY