Endurance training and antioxidants of lung

Summary Mice and rats were adjusted to daily treadmill training programs, which were heavy enough to increase the oxidative capacity of skeletal muscles. Endurance training did not affect the activities of catalase and glutathione peroxidase and the concentration of vitamin E in the lungs of mice and rats. Thus increased ventilation and oxygen utilization induced by exercise training do not modify lung antioxidants, in contrast to hyperoxia and hypoxia.This study was supported by the Academy of Finland and the Research Council for Physical Education and Sport (Ministry of Education, Finland). We thank Mr Matti Virtanen for skillful technical assistance.     

Effect of exercise training on the chronotropic response of isolated rat atria to atropine

Summary Atria isolated from rats after 7 weeks of exercise training beat at a slower rate than did atria from sedentary controls. Atria from exercised rats showed a significant acceleration in response to atropie.This study was supported by a grant from the Genesee Valley Heart Association.     

Conditioned suppression: Dissociation of learning in baclofen treated rats

Summary In rats, baclofen induced a memory deficit related to a dissociation of learning. Baclofen given prior to training or prior to testing had no effect on the amnesia elicited by diazepam.     

Chronic exercise does not alter the chronotropic response of isolated rat atria to catecholamines

Summary Atria isolated from rats after 7 weeks of exercise training beat at a slower rate than did atria from sedentary controls. There is no significant difference between the chronotropic responses of the 2 groups to epinephrine or morepinephrine.This study was supported in part by a grant from the Genesee Valley Heart Association.     

The effect of dimethyl sulfoxide on tissue distribution of gentamicin

Summary Dimethyl sulfoxide (DMSO) and gentamicin were administered to rats i.p. No significant differences in gentamicin tissue concentrations were found between rats receiving DMSO and gentamicin, and rats receiving gentamicin alone. DMSO does not increase the tissue concentrations of gentamicin.     

Hypothalamo-hypophyseal-gonadal function in the rat following administration of the novel and selective D-1 agonist CY 208-243

The effects of the novel and selective dopamine D-1 agonist CY 208-243 on the rat hypothalamo-hypophyseal-gonadal (HHG) axis were studied. CY 208-243 did not modify the concentration of luteinizing hormone (LH) in serum from female or male rats, and had no effect upon opiate antagonist-induced stimulation of LH secretion in male rats. CY 208-243 did not inhibit ovulation in cycling female rats. Thus, D-1 receptor activation by systemic drug administration does not alter HHG function in rats.     

Hypothalamo-hypophyseal-gonadal function in the rat following administration of the novel and selective D-1 agonist CY 208-243

Summary The effects of the novel and selective dopamine D-1 agonist CY 208-243 on the rat hypothalamo-hypophyseal-gonadal (HHG) axis were studied. CY 208-243 did not modify the concentration of luteinizing hormone (LH) in serum from female or male rats, and had no effect upon opiate antagonist-induced stimulation of LH secretion in male rats. CY 208-243 did not inhibit ovulation in cycling female rats. Thus, D-1 receptor activation by systemic drug administration does not alter HHG function in rats.     

Studies on chemically induced tumors in rats: I. Heterogeneity of tumor cells and establishment of syngeneic, tumor-specific cytotoxic T cell clones

Sarcoma P1 was induced in DA rats by DMBA. Anti-P1 antibodies were produced in DA rats, purified via fixed tumor cells and used to induce anti-idiotypic antibodies in syngeneic rats. The anti-idiotypic antibodies were used to generate cytotoxic, P1 specific DA T cells in vitro. These cytotoxic T cells and P1 tumor cells were cloned by limiting dilution. Using the DA anti-P1 specific cytotoxic T cell clones, we were able to characterize 2 types of P1 tumor cell clones, namely those which were susceptible and those which were resistant to the P1 specific cytotoxic T cells. Cytotoxic T cell injected i.v. into syngeneic DA rats could not prevent the development of lethal P1 tumors.     

Effect of pretreatment with acetylsalicylate on surgical bleeding and peroperative mortality in rats undergoing kidney transplantation.

42 rats were pretreated with L-ASA before kidney transplantation, 43 rats acted as controls. 9 rats with L-ASA, but no control rats, died with i.p. haemorrhage. However, in animals surviving the operation, the intraoperative blood loss did not differ significantly between the 2 groups.     

Effect of pretreatment with acetylsalicylate on surgical bleeding and peroperative mortality in rats undergoing kidney transplantation

Summary 42 rats were pretreated with L-ASA before kidney transplantation, 43 rats acted as controls. 9 rats with L-ASA. but no control rats, died with i.p. haemorrhage. However, in animals surviving the operation, the intraoperative blood loss did not differ significantly between the 2 groups.     

Acceleration of crypt cell proliferation by acoustic stimuli

Summary Cell proliferation rates in the bases of the crypts of Lieberkuhn in the jejunum of rat were measured using a stathmokinetic technique. In rats subjected to recurring loud noise cell proliferation was more rapid than in rats not subjected to the noise.     

Methimazole treatment reduces cardiac hypertrophy and mortality without a concomitant reduction in blood pressure in established Goldblatt two-kidney one clip hypertension

The effects of methimazole, and antithyroid drug, on blood pressure and other parameters were evaluated in the established phase of Goldblatt two-kidney one clip (G2K-1C) hypertension. Methimazole was administered via drinking water for five weeks, starting five weeks after hypertension had been induced. After this period of treatment, similarly high blood pressures were observed in methimazole-treated and non-treated G2K-1C rats, despite the fact that a hypothyroid state had been achieved in methimazole-treated rats. Methimazole-treated G2K-1C rats showed reductions in heart rate, ventricular weight, ventricular/body weight ratio and mortality in comparison with rats not treated with methimazole. These results clearly demonstrate that hypothyroidism induced by methimazole: a) does not reverse G2K-1C hypertension, but b) improves the rate of survival and c) reduces relative cardiac hypertrophy, possibly by the reduction in cardiac work observed in Goldblatt hypothyroid rats.     

Methimazole treatment reduces cardiac hypertrophy and mortality without a concomitant reduction in blood pressure in established Goldblatt two-kidney one clip hypertension.

The effects of methimazole, an antithyroid drug, on blood pressure and other parameters were evaluated in the established phase of Goldblatt two-kidney one clip (G2K-1C) hypertension. Methimazole was administered via drinking water for five weeks, starting five weeks after hypertension had been induced. After this period of treatment, similarly high blood pressures were observed in methimazole-treated and non-treated G2K-1 C rats, despite the fact that a hypothyroid state had been achieved in methimazole-treated rats. Methimazole-treated G2K-1 C rats showed reductions in heart rate, ventricular weight, ventricular/body weight ratio and mortality in comparison with rats not treated with methimazole. These results clearly demonstrate that hypothyroidism induced by methimazole: a) does not reverse G2K-1 C hypertension, but b) improves the rate of survival and c) reduces relative cardiac hypertrophy, possibly by the reduction in cardiac work observed in Goldblatt hypothyroid rats.     

A rat mutant unable to synthesize vitamin C

A colony of Wistar rats with a hereditary defect in L-ascorbic acid-synthesizing ability was established. This rat, like primates and guinea pigs, lacks L-gulonolactone oxidase (EC 1.1.3.8) which catalyzes the last step of L-ascorbic acid biosynthesis. When L-ascorbic acid was added to their drinking water, the rats grew almost normally and were fertile. These mutant rats should be useful not only for nutritional and pharmacological studies on vitamin C, but also for genetic studies on the lack of this enzyme.     

补肾固齿丸对大鼠实验性牙周炎牙槽骨吸收的影响

目的观察补肾固齿丸对大鼠实验性牙周炎牙槽骨吸收的影响,进一步探讨补肾固齿丸对牙周炎的治疗机理.方法建立大鼠牙周炎模型,给予补肾固齿丸治疗,采用放射免疫法测定血清骨钙蛋白与Ⅰ型胶原交联 C端肽浓度,同时采用体式显微镜进行牙槽骨吸收分析,以评价补肾固齿丸对大鼠实验性牙周炎的治疗作用.结果经过补肾固齿丸治疗30d后,补肾固齿丸高中低剂量组血清中骨钙蛋白与Ⅰ型胶原交联 C端肽的浓度均低于牙周炎模型组(P<0.05),同时体式显微镜观察高中低剂量大鼠牙槽骨吸收总值明显低于牙周炎模型组(P<0.05),而三个剂量组之间无显著性差异(P>0.05).结论补肾固齿丸能改善牙周炎大鼠牙槽骨代谢状况,减少牙槽骨的吸收     

Different neuropathological effects of intrahippocampal injections of kainic acid and tetanus toxin

Behavioral and neuroanatomical effects of hippocampal injections of kainic acid (KA) and tetanus toxin (TT) were investigated in rats. Injections of KA resulted in both local and distant neuroanatomical damage, but not in clear signs of epilepsy; injections of TT on the other hand were followed (in some of the rats) by prolonged seizure attacks, but not by neuronal damage. Based on these results it is suggested that the widespread neuronal damage following KA lesions cannot be primarily attributed to orthodromic activation of epileptic discharges. Instead, specific properties of KA and their interactions with certain transmitters may provoke widespread neuroanatomical damage.     

The behavior of the homozygous and heterozygous sub-types of rats which are genetically-selected for diabetes insipidus: A comparison with Long Evans and Wistar stocks

Several aspects of spontaneous and conditioned behavior (food and water intake, locomotion and emotionality, passive and active avoidance acquisition and retention) of standard (albino and pigmented) rats, and rats heterozygous (HEDI) and homozygous (HODI) for diabetes insipidus, are reviewed. As would be expected, HODI rats have been repeatedly found to consume far more fluid than either HEDI or control rats. Pigmented rats appear to be more active than albinos. HODI rats exhibit less marked emotional responses than do control rats, among which the pigmented ones exhibit the highest emotionality. Light aversion is more evident in albino than in pigmented rats. No differences are found among HEDI, HODI and normal Long Evans rats. It is quite difficult to provide a clear-cut statement concerning inter-strain differences in passive avoidance behavior, possibly because of the variety of techniques employed. In any case, HODI rats do not perform worse than normal controls do. In one-way active avoidance paradigms, pigmented rats perform better than albinos, and the performance of HODI rats does not differ from that of controls. In two-way avoidance paradigms, albinos appear to outperform pigmented rats. Once again, there are no obvious differences between HODI and control animals.In addition to indicating that HODI rats may actually be less emotional than the other groups of rats reviewed here, the studies described once again fail to confirm the previously alleged functions of vasopressin in memory consolidation.     

Experimenteller Beitrag zur Frage von Nierenschäden bei Abusus von phenazetinhaltigen Schmerzmitteln

Summary In view of the chronic interstitial nephritis observed in man after years of abuse of phenacetin-containing analgesics, rats were subjected to oral loading-tests with Saridon and its active components. It was not possible, however, to induce interstitial nephritis experimentally. Trials with Saridon will be continued on rats having undergone additional renal loading-tests and in which renal damage has been previously induced.     

Fertilität reduzierende Wirkung langdauernder Noradrenalinbehandlung

Summary Albino rats of both sexes were treated with epinephrine and norepinephrine for 3 months, while the control animals received the same quantity of physiological NaCl. At the end of this period, the rats were allowed to multiply freely in each group. The number of litters was recorded in each case. While epinephrine did not alter the litter-rate, norepinephrine decreased it significantly. The effect of neural stress on reproduction and its relation to the adrenomedullar hormones is discussed.     

Serotonergic and cholinergic interaction in the regulation of pituitary-adrenal function in rats

It has been proposed that the central serotonergic inputs which modulate pituitary-adrenal secretion are mediated by cholinergic neurons. We have tested this hypothesis in intact rats. Male Sprague-Dawley rats were injected with cholinergic and serotonergic agents which enhanced transmitter function and with receptor blocking agents. Agents were injected, singly and in combination, into both unstressed and stressed animals. Since the response to cholinergic agents might be due to changes to vasopressin release, Brattleboro (vasopressin deficient) rats were also injected with cholinergic agents. The level of plasma corticosterone at 1-h post-injection was determined. Results indicate that the serotonin receptor blockade decreased the stimulatory, cholinergic effect of physostigmine. Cholinergic receptor blockers did not significantly reduce the corticosterone rise induced by 5-hydroxytryptophan. These results do not support the hypothesis of cholinergic mediation of serotonergic input. Nicotinic and muscarinic receptors appeared to exert opposing influences on the system. The nicotinic receptor antagonist was able to block the stimulatory effect of physostigmine. The muscarinic receptor antagonist significantly elevated plasma corticosterone levels. No differences were found in the effect of physostigmine on Brattleboro rats as compared to controls. These data are interpreted as suggesting that 1) the acetylcholine-induced stimulation of pituitary-adrenal function is mediated, in part, by serotonergic neurons; and 2) stimulation of nicotinic receptors is facilitatory whereas stimulation of muscarinic receptors is inhibitory to pituitary-adrenal function.