摘要:

Four chimpanzees were trained to respond on three operant schedules of positive reinforcement. Amounts of a marihuana extract containing from 200 to 800 µg/kg (–)-Δ9-trans-tetrahydrocannabinol (Δ9-THC) were orally administered 2.5 h prior to experimentation. Although the separate reinforcement schedules were differentially sensitive to the drug, significant behavioral effects were produced by the smallest Δ9-THC doses used. It was concluded that the behavioral effects of Δ9-THC, at oral doses within the effective minimum range for man, can be adequately assessed in chimpanzees and that the chimpanzee may be a suitable substitute for man in the study of long-term effects of mar

ISSN:0031-7012    

DOI:10.1159/000136301

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Repeated injections of sufficient doses of tyramine (20 mg/kg i.p.) to rats at 15-min intervals for a total of 12 doses, deplete the heart norepinephrine (NE) stores by about 90 %. Following the last dose of tyramine, the concentration of heart NE increased progressively as the net result of the processes of synthesis and loss. The net rate of NE repletion is given by the equation: log[(([NE]∞ – [NE]) [NE]∞)/[NE]∞] –kt/2.303 The calculated ‘k’ constant times the NE steady-state level corresponds to the NE synthesis rate ‘K’. This rate is identical with that determined from the decline in levels after α-methyltyrosine (α-MT) and from the loss of 3H-NE after labelin

ISSN:0031-7012    

DOI:10.1159/000136302

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Diphenylphosphoric acid esters of choline, of α-methylcholine, of β-methylcholine and of homocholine were examined for their effects on skeletal muscle. Their in vitro effects on frog rectus abdominis and their in vivo action on chicks showed that the first three esters were competitive antagonists of acetylcholine, whereas the last was a depolarizing blocking agent. The presence, in these compounds, of a single quaternary ammonium group is significant to structure-action relationships amongst curarimimetic agent

ISSN:0031-7012    

DOI:10.1159/000136303

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

This study describes the effect of several inducing-agents on drug metabolism in Sprague-Dawley and Long-Evans rats. DDT, eucalyptol, and phenobarbital are less active in Long-Evans than in Sprague-Dawley rats. 3-Methylchol-anthrene, on the other hand, induces drug metabolism at similar extent in both strains. Experiments with phenobarbital show that the reduced reactivity of Long-Evans rats is dependent neither on the plasma and liver concentration of the inducing agent nor on time. However, a different reactivity to phenobarbital induction has been demonstrated in Long-Evans of 2 different sources.

ISSN:0031-7012    

DOI:10.1159/000136304

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Maximal aniline hydroxylase and hexobarbital oxidase activities were evident in rats fed between 1 and 10 µl arachidonate/day whereas cytochrome P-450 was at a maximum between 10 and 30 µ\l day. NADPH cytrochrome C reductase and cytochrome P-450 reductase activities were unaltered in a significant way by this essential fatty acid. Cytochrome P-450 of microsomes from rats fed increasing quantities of menhaden oil tended to increase but aniline hydroxylase was depressed in both fat-free fed rats and those given 100 αl/day and hexobarbital oxidase was depressed only in livers from rats fed the fat-free diet. Neither cytochrome P-450 reductase nor NADPH cytochrome C reductase was affected by menhaden oil ingestion. Glucose-6-phosphate dehydrogenase activity was elevated in nearly all doses of arachidonate and menhaden oil below 100/4/day. It appears that dietary fatty acids such as arachidonate and docosahexaenoate (menhaden oil) are involved in the synthesis or maintenance of hepatic drug metabolizing enzym

ISSN:0031-7012    

DOI:10.1159/000136305

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Antagonism of hexamethonium (C6) action by choline was investigated using rabbit sciatic nerve-gastrocnemius muscle and conscious rat blood pressure preparations. The neuromuscular blockade caused by C6 was markedly reduced by choline pre-treatment and the hypotensive effect elicited by C6 was abolished by the same treatment with choline. These results support the hypothesis that C6 paralyzes cholinergic nerves via blockade of choline uptake and the subsequent synthesis of acetylcholine. However, the actions of C6 are slightly different from those of hemicholinium, since choline does not reverse the action of C6 when it is given after the administration of C6. This could be due to stronger binding forces of C6 toward the nerve ending than occurs in hemicholinium.

ISSN:0031-7012    

DOI:10.1159/000136306

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

The effect of calcium and oestrogen therapy on theexcretion of total hydroxyproline, calcium and phosphorus in 23 asymptomatic postmenopausal women has been evaluated. A temporary significant reduction in total hydroxyproline and phosphorus excretion in the group with calcium therapy has been observed. No effect in the oestrogen-treated group has been observed. Therapy with calcium supplements seems to be of value. An interrupted calcium therapy, however, is to be preferred to a continuous therapy.

ISSN:0031-7012    

DOI:10.1159/000136307

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

The injection of epinephrine (1 mg/kg) into rats caused a significant increase in the distribution ratio (DR) of previously injected 1-aminocyclopentanecarboxylic acid (ACPC) and α-aminoisobutyric acid (AIB) within 2 h. At the same time epinephrine depressed the concentration of AIB in serum. Epinephrine did not alter ACPC concentration or distribution ratio in the diaphragm of partially eviscerated rats with intact livers and kidney. Additional amino acid transport studies were conducted in vitro using ‘intact’ diaphragm preparations from rats and Krebs-Ringer bicarbonate buffer, pH 7.4, at 37°C. AIB uptake into the intact isolated diaphragm was linear during the first 90 min of incubation. Epinephrine (EPI), 183 µM, caused a 20- to 30-percent decrease in the rate of AIB uptake during this time. EPI concentrations of 1.83 to 91.3 µM had no significant affect on AIB transport during a 60-min incubation period. EPI, 183–787 µM diminished uptake 30%. EPI, 183 µM, had a similar effect on AIB transport into diaphragms from adrenalectomized rats. Varying glucose concentrations from 2.2 to 17.8 mM did not significantly alter the inhibitory response elicited by epinephrine. However, the response to epinephrine was abolished by either 0.0 or 36.5 mM glucose. Isoproterenol, 161–403 µM did not significantly alter AIB transport in this system. On the other hand norepinephrine, 119 to 239 µM. caused a 20-percent increase of AIB uptake by the isolated diaphragm. Additionally, glucagon (11.5 µM) caused a 150-percent increase in AIB uptake into diaphragm muscle in vitro. Injecting 1 mg of EPI/kg 60 min before the preparation of the diaphragm caused a 25-percent increase in AIB uptake. AIB concentrations in the buffer medium were not significantly altered by hormone treatments in any of these studies. These results suggest that the increase in AIB uptake caused by injecting EPI may be an indirect action of the catecholamine and that the direct effect of EPI on AIB transport into diaphragm is inhibitory. The results further suggest that the indirect EPI effect in vivo might be ca

ISSN:0031-7012    

DOI:10.1159/000136308

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Amplitude of accommodation and pupillary size were measured before and during therapy with nortriptyline in 41 depressed in-patients. Pupillary size showed no change after two weeks therapy. There was a small decrease in amplitude of accommodation during therapy in the younger age group (<45 years) while accommodation remained unchanged in the older age group. Subjective complaints of blurred vision were not significantly correlated to objective changes in accommodation. There was a positive correlation between decrease in amplitude of accommodation and plasma concentration of nortriptyline.

ISSN:0031-7012    

DOI:10.1159/000136309

出版商:S. Karger AG    

年代:1972

数据来源: Karger

摘要:

Totally isolated canine stomachs, perfused with homologous blood, were used for the study of potentiation between pentagastrin and histamine. These stimulants were infused into the gastric arterial system separately, or combined. Gastric secretion and perfusion blood were sampled every 30 min for biochemical analyses Combination of pentagastrin plus histamine gave significantly higher outputs of HCl than could be accounted for on the basis of summation of stimulatory effects. True potentiation, with regard to gastric juice volume and HCl output, occurred when two stimuli were infused simultaneously. Gastric hypersecretion of H+ was associated with increased O2–consumption by the stomach and by the alteration of the physiological relationship between the pH of arterial and venous blood sampled from gastric vessels. It was concluded that the totally isolated canine ex vivo stomach, perfused with homologous blood, is a suitable experimental preparation for the study of potentiation effects between two humoral gastric secretagogue

ISSN:0031-7012    

DOI:10.1159/000136310

出版商:S. Karger AG    

年代:1972

数据来源: Karger