摘要:

The effect of porcine pancreatic glucagon on the formation of pancreatic juice and bile was studied in conscious rats. When the rats were fasting, intravenous infusions of glucagon were associated with depressions in the flow, and in the output of bicarbonate and protein in pancreatic juice (p < 0.001). By contrast, infusions of glucagon to rats during feeding were associated with increases in the formation of pancreatic juice, particularly the volume and bicarbonate fraction. The responses were greater than those recorded in rats that did not receive exogenous glucagon during feeding (p < 0.01). Glucagon did not appear to influence the formation of bile.

ISSN:0008-4212    

DOI:10.1139/y73-001

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effect of vitamin A status on hepatic drug metabolism was studied in rats. Animals were fed diets with and without vitamin A for 20 and 25 days. Weight gains of control and deficient animals were not significantly different, whereas liver vitamin A levels had decreased to less than 10% of control animals after 20 days and were essentially zero after eating the deficient diet for 25 days. Aniline metabolismin vitroand aminopyrine metabolismin vitroandin vivowere significantly lower in male weanling rats fed a vitamin A deficient diet for 20 days. No alteration inin vitro p-nitrobenzoic acid metabolism was noted after 25 days on the test. Vitamin A deficiency did not alter microsomal protein levels or cytochromecreductase activity but deficient animals did have a lower microsomal cytochrome P-450 content. Hepatic enzyme activities and cytochrome P-450 levels were restored to values approaching those found in control animals by feeding vitamin A deficient rats the vitamin A containing diet for 21 days. Liver vitamin A levels were markedly increased after re-feeding studies but were still significantly lower than control animals.

ISSN:0008-4212    

DOI:10.1139/y73-002

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The purpose of this study was to evaluate the effect of Δ9- and Δ8tetrahydrocannabinol (THC) on some isolated muscles. The results observed show that Δ9- and Δ8THC do not have agonistic activity on the vas deferens, the phrenic nerve – diaphragm, and the ileum preparations. On the other hand, both compounds produce a transient potentiation followed by the inhibition of the acetylcholine-induced contraction as well as a potentiation of the musculotropic activity of noradrenaline on the isolated vas deferens. Furthermore, we have observed that Δ8THC reverses the anti-cholinergic action of atropine, conteracts the anti-angiotensin activity of morphine, and finally, abolishes the potentiation of noradrenaline produced by cocaine. On the phrenic nerve – diaphragm preparation Δ9THC does not modify the contraction produced by nerve stimulation but alters the effect of physostigmine, an anti-cholinesterase inhibitor.

ISSN:0008-4212    

DOI:10.1139/y73-003

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

In order to calculate the intracellular concentration of accumulatedL-alanine, the extracellular space (inulin-14C) of frog intestine was measured. To check the validity of the technique, frog liver and gastrocnemius were used too. By scraping proximal portions of intestine, the inulin space was found to be similar (around 20% of total tissue water) in both the muscle layer and the mucosa. The mucosal epithelium is an imperfect barrier to inulin while the serosa is very permeable. These results suggest that the interstitial solute concentration is best approximated by equating it to that of the serosal solution. Thein vitroinulin space, compared to thein vivoone, increases with time, as does the cellular hydration. The data obtained from measurements of extracellular space and fromL-alanine uptake show that the intracellular amino acid is in a free state.

ISSN:0008-4212    

DOI:10.1139/y73-004

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The inhibitory effect of sciatic and ulnar nerve afferent stimulation on the firing frequency of sympathetic preganglionic neurons was studied in anesthetized or unanesthetized decerebrate cats, with intact spinal cords or with spinal cords sectioned at C2. The spontaneous firing and the firing evoked by antidromic stimulation, by iontophoretic glutamate, and by mechanical injury could be depressed, in the preparations both with intact and sectioned spinal cord. The depression was not preceded by excitation. The minimum stimulus strength required for the inhibition was, on average, 15 times the nerve threshold. The inhibition elicited by single shocks lasted several hundred milliseconds and was longer in the intact than in the spinal preparation. The results show that the neural pathway used by high threshold somatic afferents for inhibition of the sympathetic preganglionic neurons is complete within the spinal cord and suggest that the inhibition is probably acting on the preganglionic neuron membrane.

ISSN:0008-4212    

DOI:10.1139/y73-005

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The influence of phenobarbital pretreatment was studied on the sensitivity of the isolated guinea pig vas deferens to various agonists. The results reported in this communication show that such pretreatment produces an unspecific supersensitivity to catecholamines, histamine, and acetylcholine. Furthermore, the anticholinergic actions of atropine, the antihistaminic action of diphenhydramine, and the α-blocking property of phentolamine are reduced by the phenobarbital pretreatment. In conclusion, it is proposed that the supersensitivity observed is of the postsynaptic type and probably related to the facilitation of the energetic process involved in the smooth muscle contraction.

ISSN:0008-4212    

DOI:10.1139/y73-006

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The acute administration of 0.06 and 0.10 mMcobalt chloride to an isolated guinea pig heart perfusedin vitroresults in decreased mechanical performance and substrate uptake. These findings are concordant with those of others who suspect that cobalt slows down myocardial energy metabolism and, as a result, substrate uptake. Cobalt also increased coronary vascular tonus and, as a result, coronary resistance.

ISSN:0008-4212    

DOI:10.1139/y73-007

出版商:NRC Research Press    

年代:1973

数据来源: NRC