摘要:

Summary.1. In decerebrate or nembutalized cats whose pyramidal tracts were stimulated at the medullary level the typical response in leads from the dorsal surface of the lumbar part of the spinal cord was a recruiting slow negative deflection and a subsequent positivity. The response was not influenced by a transverse section of the medulla caudal to the point stimulated, sparing only the pyramids.2. A similar response could be elicited by stimulation of the pericruciate area in the cerebral cortex. When this area was sucked out and the pyramids were stimulated after an interval allowing the cortico‐spinal fibres to degenerate, no response was obtained in leads from the lumbar cord dorsum.3. In conditioning experiments the afferent cord dorsum response to low threshold stimulation of a cutaneous nerve in the hind leg (the N1, deflection) was used as the test response. The N1, deflection decreased in amplitude when superimposed on the slow negative wave elicited from the contralateral pyramid while it was not influenced following ipsilateral pyramidal stimulation. In an analogous way a depression of the N1, deflection was obtained when the pericruciate area was stimulated. When the slow negative wave was not elicitable due to degeneration of the corticospinal fibres stimulation of the pyramid did not influence the N1, deflection.4. The results indicate that the pyramidal tract mediates a cortico‐spinal inhibitory influence on the primary afferent relay in the spinal c

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01394.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.After repeated subcutaneous injections of Hö 9980, a drug with pronounced atropine‐like properties, a supersensitivity towards adrenaline develops in the submaxillary glands of cats. The supersensitivity closely resembles that produced by section of the chorda tympani but is more marked. Evidence is given to show that the supersensitivity caused by the drug is entirely due to the parasympathicolytic activity. and it is concluded that the sensitization above the level produced by the preganglionic denervation is due to exclusion of some action of the paraspmpathetic postganglionic neurone on the gland cel

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01395.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.The spike of motor unit potentials was investigated in the human brachial biceps by means of a multielectrode containing twelve small leading‐off surfaces distributed over a length of 2.5 mm (Fig. 3).Within a distance of 0.38 mm the spike amplitude decreased to one tenth of its maximum value (Figs. 6, 7).The duration of the positive‐negative deflection of the spike averaged 136 μsec(36.50C) at the lead with maximum response. increasing by 100 μsec over the distance at which amplitude had fallen to one tenth of its maximum value (Table 2).The six times longer duration of the total motor unit potential than of its spike component is due to superposition of temporally dispersed spike potentials from more distant parts of the motor unit (Table 2).Applying volume conduction analysis to the motor unit spikes classified in three groups according to maximum amplitude, the relation was determined between spike amplitude and distance from theaxisof the potential source. The logarithm of

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01396.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.The rise in blood pressure caused by an infusion of noradrenaline in the cat is frequently followed by a marked fall in blood pressure to subnormal levels, often lasting for 20–40 minutes.The sensitivity to single injections of noradrenaline is diminished during the first part of this period. After section of the buffer nerves the fall after noradrenaline infusion is prolonged and often enhanced.Intravenous infusions of calcium chloride reduce the blood pressure fall after noradrenaline.Only a brief and moderate fall is seen in animals having received TEAB in transmission blocking doses. This fall can be abolished by small doses of ergotamine.It is concluded that the fall in blood pressure after noradrenaline is partly due to a blocking effect on transmission within the vasomotor system.Certain implications of the present observations for the therapeutic use of noradrenaline infusions in man are briefly discusse

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01397.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.5‐Hydroxytryptamine strongly stimulated intestinal motility inPleuronectesandLabrus. It was less active inAnguilla, Lophius, SqualusandRaja, and had little or no action inMyxine.Acetylcholine stimulated the isolated intestine in all species tested, although this effect was small in Squalus.Histamine contracted the intestine inPleuronectes, LabrusandGadusbut had either a small or no action inLophius, Anguilla, RajaandMyzine.Noradrenaline had only 1/30–1/100 of the inhibitory action of adrenaline on the intestine ofAnguillaandLophius. and 1/30 of the stimulating action of adrenaline on the intestine of Squalus.Substance P stimulated the intestine of all species tes

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01398.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.The subcutaneous fat from three male rats reared on a fat‐free diet and three other male rats reared on a diet containing 28 % hydrogenated peanut oil was analyzed at regular intervals for linoleic acid andconjugateddienoic acid. The content of linoleic acid declined rapidly to a low level in both groups. The level ofconjugateddienoic acid was almost constant in rats on the fat free diet, but increased to a maximum value of about 2 % in the fat of the rats receiving the hydrogenated peanut oil diet. The hydrogenated peanut oil contained less than 0.1 %conjugateddienoic acid. Thus a certain accumulation of the conjugated acid from this oil has taken place in the adipose tissue. The period in which the subcutaneous fat contains an increased amount of conjugated dienoic acid coincides with the period of growth retardation. The significance of this finding is discusse

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01399.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.In a study of the placental transfer of phosphorus in the guinea pig the transfer of inorganic phosphate from mother to foetus has been investigated from the 29th day to term with the aid of radioactive phosphorus. The inorganic phosphate in the maternal plasma was found to be the main source of phosphorus to the foetus. If most of the placental uptake of phosphate not needed in placental growth was considered to be transferred to the conceptus, enough inorganic phosphate is supplied to cover the foetal needs for phosphorus. hut the safety margin is small. especially late in gestation.The amount of phosphorus retained in foetal growth per day increases with advancing gestation. and the increase is linear from the 38th day to term. The amount retained in placental growth is nearly constant. during the period studied.If the maternal plasma, as our previous studies indicate, contains a labile, non‐diffusible phosphorus compound. which is broken down to inorganic phosphate in the course of the chemical determination. it is either present in too small quantities to influence the results, or it is utilized by the conceptuses to the same extent as the inorganic phosphate in the maternal plasma.The foetal plasma was found to contain twice as much inorganic phosphate as the maternal plasma. The transfer of phosphate front mother to foetus thus takes place against a concentration gradien

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01400.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.In a study of the placental transfer of phosphorus in the guniea pig the transfer of inorganic phosphate from foetus to mother has been investigated in the last part of gestation with the aid of radioactive phosphorus. The quantity transferred in this direction across the placenta is approximately 25 % of the amount which is transmitted from mother to foetus at the same stage of gestation. The amount transferred from mother to foetus is about equal to the amount retained in foetal growth plus the amount returned to the mother. The return of phosphate from foetus to mother is facilitated by the concentration gradient from the foetal to the maternal plasma.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01401.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Summary.In gastric fistula dogs the gastric motor responses to carbachol, mecholyl and adrenaline were recorded under nembutal anaesthesia in repeated experiments before and after transthoracic vagotomy. Observations were made up to 200 days after operation.The threshold doses of the drugs mentioned for motor responses were markedly lowered by vagotomy and the responses to graded doses showed a corresponding increase as compared with preoperative responses.Increased sensitivity was usually apparent within the first 24 hours after vagotomy and maximal values were in most cases attained within the first 20 days. Later on, a decline in supersensitivity was observed, but preoperative values were not reached within 200 days after vagotomy. With carbachol and mecholyl the decline was pronounced; with adrenaline it was very slight.Similar experiments were performed on conscious dogs, using carbachol and pilocarpine. The results for carbachol agreed closely with those obtained in experiments performed under nembutal. The threshold dose of pilocarpine was found to be considerably reduced after vagotomy.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1957.tb01402.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY