摘要:

AbstractThe effects of intravenous sodium salicylate administration on plasma concentrations of insulin, free fatty acids (FFA) and glucose were studied in intact, anaesthetized dogs both during basal and isoprenaline stimulated lipolysis. In both situations sodium salicylate reduced the plasma concentrations of insulin. The reduction was associated with decreased plasma FFA concentrations and FFA turnover rate, while plasma glucose concentrations remained unaltered. The reduced plasma insulin concentrations effected by sodium salicylate is most likely secondary to the concomitant fall in plasma FFA concentrations due to inhibition of FFA mobilization from adipose tissue.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06198.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractPregnancy is accompanied by a reduction in uterine noradrenaline, and the study was undertaken to investigate associated structural and functional integrity of the sympathetic nerves in the organ. The formaldehyde‐induced fluorescence of adrenergic nerves was studied in different uterine regions before and afterin vitroincubation or injection with α‐methyl‐noradrenaline in pregnant and puerperal guinea‐pig uterus at 6 time periods, from early pregnancy (about 20 dayspost coitum) to 3 monthspost partum.The changes were related to the position of the fetuses, which were often present in only one of the two uterine horns. There was a drastic loss of fluorescent adrenergic nerves in myometrial tissue from horns distended by fetuses. Attemps to restore this fluorescence by incubation or injection with α‐methyl‐noradrenaline were essentially ineffective. Tissues from uterine regions outside (and not distended by) fetuses (in the case of early pregnancy), from horns devoid of fetuses (in the case of unilateral pregnancy), and from the cervix also lost their noradrenaline‐fluorescent nerves, but this occurred at a much later stage of pregnancy. After treatment with α‐methyl‐noradrenaline, a fluorescent plexus of sympathetic nerves could be restored to a considerable extent in these latter tissues. In puerperal animals the horn that had been devoid of fetuses regained its endogenous fluorescence much faster, and ihe uptake of α‐methyl‐noradrenaline was more efficient, than in the horn which had contained fetuses. In this latter horn clear signs of restoration of endogenous adrenergic fluorescence and a clear uptake capacity was not found until 3 months after delivery. In the tubal end of the uterus, the reduction in the number of fluorescent nerves was only insignificant, and the region thus clearly differed from the rest of the uterus. It is concluded that (1) there are clear regional differences with regard to the disappearance of the noradrenaline transmitter in the uterus, (2) this disappearance in early pregnancy is related to the position of the conceptus, and (3) the changes involve de‐and regenerative phenomena as well as alterations in transmitt

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06199.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe postnatal development of the inferior oblique muscle in the cat has been studied with physiological and histochemical teckniques. This paper describes the changes with age in isometric twitch and tetanic response characteristics. The twitch amplitude increased and the twitch contraction time (ct) and half‐relaxation time (hrt) decreased almost linearly from birth to adulthood. The relation between the strength of nerve stimulation and twitchctandhrtchanged during development with a threshold slow response appearing at 10 weeks. Twitch responses in cats 6 weeks of age or older were of longer duration than in younger cats, in spite of the longerctandhrtin young cats. Fusion frequency of the tetanic response reached a constant level in muscles 6 weeks or older. The maximum rate of tension rise remained the same from birth to 6 weeks of age and later increased markedly up to 20 weeks of age. The contracture induced by succinylcholine was the same in muscles of all ages. These data were related to previous findings on the postnatal development of fast and slow muscles and motor units in the hindlimb of the cat. A differentiation of the development of fast and slow eye muscle fibres is suggested. Slow fibres seemed to have completed their maturation at about ten weeks of age, while the development of fast fibre properties continued, probably up to the adult stag

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06200.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe changes with postnatal age in post‐tetanic potentiation (PTP) and fatigue of the inferior oblique muscle have been studied in the cat. PTP of the twitch amplitude increased steadily with age up to 20 weeks after birth. Twitch contraction time (ct) and half relaxation time (hrt) was not significantly changed. The potentiation of the tetanic response also became more prominent with age. The young muscles (10 weeks and below) were slightly more susceptible to fatigue than older muscles, but recovery was rapid in muscles of ail ages. Intensive stimulation induced post‐tetanic depression of twitch responses in muscles older than 1 week, but none in the muscles of new‐born cats.Ctandhrtwere greatly prolonged in muscles above six weeks of age. In these muscles, but never in the very youngest, repetitive firing could be observed in response to post‐tetanic single nerve stimulation. The results are compared with those obtained in similar experiments on hind‐limb muscles by other workers. They further support the idea, raised in a previous paper, that slow eye muscle fibres develop quicker and reach maturity earlier than fa

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06201.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThiamine was found to bind to the isolated nicotinic receptor (nAChR) fromTorpedo marmorata(KD‐ 3 ‐5 10‐5M). The binding was reversible and inhibited by α‐neurotoxin fromNaja naja siamensis.Acetylcholine binding was not inhibited by thiamine. When thiamine (5 × 10‐4M) was applied to frog sartorius muscles a decrease of miniature end plate potential amplitudes was seen. This effect was readily reversible after the perfusion fluid of the muscle was changed to normal Ringer solution. Thus both biological and electrophysiological studies indicated a binding of thiamine t

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06202.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractPost‐tetanic potentiation (PTP) of single muscle twitches after “tetanic” stimulation at 1 to 20 Hz in rat masseter muscle has been studied. PTP was inhibited by d‐tubocurarine (2–6 μg/kg), hexamethonium (1.75‐2.25 mg/kg), succinylcholine(5–7μg/kg), prostigmin (1.0–1.5μg/kg), lidocain (3–4 mg/kg) and ouabain (215–240 μg/kg). The doses did not affect the control twitches. Prostigmin could not reverse the blocking effect on the PTP caused by these drugs. Atropin was without any effect on the PTP. The nicotinic receptors mediating PTP differ from both end‐plate and ganglionic receptors since drugs blocking both types of receptors are effective. The sensitivity to the blocking agents is higher or the same (in the case of hexamethonium) as for the two other types of nicotinic receptors. Thus the PTP is dependent on activity of a “nicotinic” receptor active during physiological conditions, suggesting the presence of an additional mechanism for neuromuscular tran

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06203.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe total body hematocrit has been reported to be 85–90% of packed cell volume (PCV) in several species. We have found similar values in rabbits. An “extra” plasma volume must exist somewhere in the vascular bed to explain this observation. We have looked for such an extra plasma volume in the pulmonary vasculature. The dynamic hematocrit was estimated in isolated, perfused rabbit lungs from distribution volumes for plasma and erythrocyte tracers. Estimation was also obtained from indicator‐dilution curves using bolus‐injections of such tracers avoiding their recirculation. It was thus possible to calculate mean transit times for the tracers from their dilution curves directly or applying monoexponential extrapolation from the first part of the downslope of the curves. The dynamic hematocrit of the lung vessels was about 94% of perfusate PCV and there was no difference between the results obtained by the different methods. We concluded that in the rabbit only a very small part of the extra plasma volume is located in the lung vessels. The lung plasma volume is not underestimated by the indicator‐dilutio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06204.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractInduction of alloxan diabetes in 5 lactating goats resulted in reduced milk yields in 3 of the animals, while the yield was unchanged in two. After treatment of the diabetic goats with insulin for 4–5 days–the last 24 h intravenously–lactose secretion returned to the control values before alloxan administration provided that normoglycemia developed. In 2 experiments infusion of a large dose of insulin caused hypoglycemia and a 20–30 per cent reduction in lactose secretion rates. In the course of 1 h after withdrawal of the insulin infusion, patent signs of insulin deficiency developed as evidenced by steadily increasing plasma glucose concentrations. Nevertheless, lactose secretion continued at the same rate as during insulin infusion for the 4 h studied after discontinuation of the insulin infusion. In the goats where lactose secretion was reduced due to insulin‐induced hypoglycemia, lactose secretion returned to control values when following discontinuation of insulin infusion the plasma glucose concentrations increased into normal and diabetic ranges. It is concluded that during insulin deficiency of short term duration, mammary lactose secretion was maintained at a normal rate. Since lactose is the major product of mammary glucose utilization, it is suggested that glucose uptake in the mammary gland was not reduced by short term insulin d

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06205.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe gross morphology, innervation pattern and contraction properties of lumbar back muscles in the cat were investigated. The medially located multifidi and interspinales are formed by short bundles interconnecting adjacent vertebrae. Laterally located bundles composing longissimus and iliocostalis are attached to the spinous processes by a fascial layer and to the pelvic bone by a well developed intermuscular septum. Different spinal segments innervate the various sections along the muscles in such a way that the myotomes composing a muscle belly seem to be arranged after one another, in a row. The contraction time of a maximal isometric twitch is 34 ms for multifidi and interspinales and 29 ms for longissimus and iliocostalis. No large segmental variations of contraction times were found. The time course of twitch responses and a study of reflex contractions in middle and lower sections of lateral muscles indicate the presence also of a slowly contracting portion located to the longissimus. The initial muscle length is more decisive for the twitch amplitude of medial than of lateral muscles. In medial muscles summation of individual twitches starts at a stimulus frequency of 10–15 Hz and apparent fusion occurs at about 50 Hz. For lateral muscles corresponding values are 15–20 Hz and about 70 Hz. The contractile tension declines markedly in all muscles during a 10 min period of stimulation at 5

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06206.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA histochemical analysis has been performed of the activity of myofibrillar ATPase, NADH2tetrazolium‐reductase, succinic dehydrogenase and phosphorylase and of the content of fat and glycogen in the muscles of the cat's lumbar back region. The correlation between the fiber composition and the previously studied contraction properties of the muscles was analyzed. All muscles contain fibers with a low activity (type I) and such with a high activity (type II) of myofibrillar ATPase following preincubation at pH 9.4. Type II fibers showed either a low (type II A) or an intermediate (type II B) reaction when stained for ATPase, preincubation at pH 4.6. Type 1 fibers have a high, II A an intermediate‐high and II B fibers a low activity of oxidative enzymes. The longissimus, iliocostalis and sacrocaudalis dorsalis lateralis muscles are characterized by high percentages of type II B fibers and low proportions of type I and type II A fibers. The central region of the longissimus which is connected to a well developed intermuscular septum is composed of a high proportion of type I fibers. The multifidi, interspinales and intertransversarii mediales muscles have higher proportions of type I and type II A fibers than the other muscles in the reg

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1978.tb06207.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY