Search PubMed⌕ Search

Biomedical subjects

D Varonos

Publications and source records attributed to D Varonos.

At least 19 recordsLinked to original sources
PubMed1992

Liver thymidine kinase activity after cadmium-induced hepatotoxicity in rats.

Intraperitoneal (i.p.) administration of a cadmium (Cd) salt at concentrations of 1.0, 2.5 and 4.0 mg CdCl2/kg body wt. caused severe liver injury in rats 24 h after administration. The toxic effects were most evident in the intermediate dose of 2.5 mg. Thymidine kinase (TK), the key enzyme of the salvage pathway of DNA biosynthesis, was affected in all Cd-treated groups. TK activity presented lower values at the highest Cd-induced hepatotoxicity.

Animals↗
PubMed1990

Behavioural changes on diet selection and serotonin (5-HT) turnover in rats under pizotifen treatment.

The effects of pizotifen on protein and carbohydrate self-selection in rats over a seven-day period, and on 5-HT turnover was studied. Four groups of male Wistar rats were individually caged and ad lib fed with a standard (SD) and (50%) carbohydrate-enriched diet (CED), sweet (diet group I) or not (diet group II). Food intake was measured daily 4 hr after IP injection of pizotifen (2.5 mg/kg) or vehicle. 5-HT and 5-HIAA in the hypothalamus (Hy), striatum (St) and hippocampus (Hi) were assayed on the 8th day of the experiment. Pizotifen increased the consumption of SD. The absolute intake of CED remained totally and daily unchanged, while the percentage proportion was reduced. Total food intake was increased by the drug which seemed to affect the proportion rather than the absolute amounts of carbohydrate and protein consumed. This effect was independent of the carbohydrate taste. There was a decrease of 5-HT levels in the Hi, while 5-HIAA/5-HT ratio was increased in the Hy and in the Hi of animals that consumed sweet carbohydrate. The above data suggest a role of pizotifen on 5-HT central metabolism and diet selection and support the view that changes of 5-HT metabolism in the Hy and Hi are responsible for protein selection and the regulation of SD/CED ratio, but they cannot explain drug's effect on total food intake.

Animals↗
PubMed1987

GABA-ergic mechanisms in the central control of cough.

The antitussive activity of gabalinoleamide (Gabalid U CB) was studied in 40 non-anaesthetized cats. The antitussive action of the substance was compared to that of codeine (Codein Spofa). Cough was induced by mechanical stimulation using a chronic tracheal cannula. Single cough parameters were evaluated from changes in the side tracheal pressure. When gabalinoleamide was administered in a dose of 100 mg/kg b.w. intramuscularly all the studied parameters of cough showed a statistically significant decrease, only the intensity of maximum cough effort remained unaffected. Gabalinoleamide administered in the same dose induced a statistically significant decrease of respiratory frequency and breathing amplitude, and prolonged the cycle of breathing by delaying the expiratory phase. Higher doses (200 and 300 mg/kg b.w.) did not have an increased cough suppressing effect. The quality and quantity of cough parameters were similar after codeine and gabalinoleamide.

Animals↗
PubMed1985

Diazepam-induced place preference conditioning: appetitive and antiaversive properties.

The place conditioning paradigm was used to examine the reinforcing properties of diazepam. Rats were injected with diazepam (0.5-5.0 mg/kg, IP) and 30 min later were confined for 30 min to one side of a shuttle box, in which each of the two compartments had distinctive features. On alternate (control) days they received vehicle injections and were confined for 30 min to the opposite side. At almost all doses tested, diazepam produced place preference for the distinctive compartment that had been previously associated with the drug. Preference for the drug side developed regardless of whether diazepam was paired or unpaired with the least-preferred side, and regardless of whether testing was carried out in the undrugged or in the drugged state. The rats preferred the drug side over a novel compartment, but they did not change their initial preference for the side when diazepam was given after removal from the training box. Animals injected with meprobamate (70 mg/kg, PO), a non-benzodiazepine anxiolytic, also developed conditioned preference for the drug side, comparable to that seen following cocaine hydrochloride (10 mg/kg, IP). The diazepam (2.5 mg/kg)-induced place preference was antagonized by CGS 8216 (3 mg/kg, IP), picrotoxin (2 mg/kg, IP) and naloxone (0.8 mg/kg, SC), injected 3 min before and 15 and 20 min after diazepam respectively. Sodium valproate (200 mg/kg, IP) did not influence diazepam (1 mg/kg)-induced place preference. Sodium valproate by itself had marginal effects on place conditioning. Picrotoxin and naloxone, but not CGS 8816, produced place aversion which, in the case of picrotoxin, was due to state dependent learning.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Chlorimipramine, electroconvulsive shock and combination thereof: differential effects of chronic treatment on apomorphine-induced behaviours and on striatal and mesocortical dopamine turnover.

We studied the influence of different pretreatment regimens (Chlorimipramine-Cmi, electroconvulsive shock-ECS, and Cmi + ECS all regimens being applied for either 2 or 15 days) on the open field behaviour, on the striatal and on the prefrontal dopamine-PFC DA turnover in rats injected with either apomorphine-AP 25 micrograms/kg (stimulating presynaptic DA receptors), AP 200 micrograms/kg (stimulating post-synaptic DA receptors), or vehicle (control). In the controls, AP 25 micrograms/kg reduced the locomotor activity and the striatal, but not the PFC DA turnover. AP 200 micrograms/kg increased the locomotor activity and reduced the striatal but not the PFC DA turnover. Short-term pretreatment: ECS and Cmi + ECS prevented the decrease of striatal DA turnover after AP 25 micrograms/kg. No other influence of any pretreatment on behaviour or DA-turnover became significant. Long-term pretreatment: Chronic Cmi: marginally increased the open field behaviour and marginally decreased the PFC DA turnover; significantly increased the effect of AP (200 micrograms/kg) on striatal DA turnover and the effect of AP (25 and 200 micrograms/kg) on PFC DA turnover. Repeated ECS: decreased locomotion and rearing and increased PFC DA turnover; increased the effect of AP (200 micrograms/kg) on locomotion and on striatal DA turnover; decreased the effect of AP (25 and 200 micrograms/kg) on PFC DA turnover. Chronic Cmi + ECS: decreased locomotion and rearing and marginally decreased PFC DA turnover; increased the effect of AP on hyperlocomotion and on striatal DA turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Effect of a new GABA-ergic substance gabalid on brain bioelectric activity of cat.

The effect of the GABA-ergic substance gabalid on the bioelectric activity of cats was studied using electrodes introduced into substantia nigra (SN), nucleus caudatus (NC), Amygdala basolateralis ( Abl ), mesencephalic reticular formation (MRF) and sensor motor cortex (Sm). Gabalid was administered i.p. in doses of 100 to 200 mg/k increased amplitude and frequency of spontaneous and evoked EEG activity in NC. Suppression of mean amplitude, driving reaction and evoked potentials was observed in Abl . Most expressive were the changes in the ECoG activity. We observed many regularly appearing bursts of high-amplitude alow "spindles" and an increase in the number of medium and high-amplitude waves.

Animals↗
PubMed1983

Olfactory involvement in learning processes.

The purpose of this study is to investigate the existing relations between olfaction and acquisition of the two-way conditioned avoidance response (CAR). For this investigation we have used white adult male Wistar rats. Taking into consideration that several structures of the limbic system participate in learning and memory processes and also that olfactory pathway is believed to have connections with the limbic system, we thought it would be interesting to investigate, if peripheral anosmia influences the performance of rats in the two-way avoidance response. It was shown that peripheral anosmia in rats impaired conditioned avoidance response.

Animals↗
PubMed1982

Effect of beta-adrenergic blockade on physiologic growth in the Wistar rat.

The effect of propranolol (Pr) on body weight was studied in 144 Wistar rats of both sexes from weaning to 17 weeks of age. Pr was administered to 77 of these rats (chosen at random), in a dose of 100 mg/kg body weight daily. Body weights were monitored every third day throughout the study. During their 17th week of age, all the rats were weighed for the last time and then sacrificed. The following organs were carefully dissected and weighed: brain, thymus, lungs, heart, liver, kidneys, adrenals, testes and ovaries. Gain in body weight was significantly reduced in the propranolol treated animals compared to control in both sexes. Organ weights were also less in propranolol-treated rats except for the kidneys of both sexes and the heart and testes of the males. However, the ratio of most organ weights per body weight was greater, indicating that the inhibition of weight gain was less severe in those organs compared to that of total body weight.

Adrenergic beta-Antagonists↗
PubMed1981

Cholinergic action of thiopental on the hypothalamohypophyseal axis.

Ten postmenopausal women were divided into two groups. In five patients (group 1) four venous blood samples were collected at 5-minute intervals before and after thiopental sodium, 6 mg/kg IV, for determination of serum levels of prolactin and thyroid-stimulating hormone. In the other five patients (group 2) the procedure followed was as in group 1, but thiopental administration was preceded by atropine, 0.1 mg/10 kg. Prolactin levels increased significantly after thiopental injection in group 1, but not in group 2. Thyroid-stimulating hormone levels in both groups remained virtually unaltered. The fact that atropine prevented the increase of prolactin due to thiopental suggests that thiopental may have an indirect effect on the hypothalamohypophyseal axis through a cholinergic mechanism.

Atropine↗
PubMed1980

Influence of liver enzyme induction caused by diphenylhydantoin and diazepam on bone mass of rats.

25 albino rats of Wistar strain were used for the study. They were divided into three groups. Animals of the first group (n = 10) were treated with Diphenylhydantoin in a daily dose of 70 mg/kg for three months. Animals of the second group (n = 10) were treated with Diazepam in a daily dose of 10 mg/kg for 3 months. Animals of the third group (n = 5) were treated with 5% acacia oil for the same period of time. Food and water consumption together with motor activity were measured. As indices of enzyme induction, D-Glucaric acid and liver weight were determined. Also the following bone indices were determined: femur Ca/femur weight, femur Ca/body weight, humerus Ca/humerus weight, humerus Ca/body weight, femur specific weight, humerus specific weight. Statistically significant alterations of bone mass were found.

Animals↗
PubMed1979

Prolactin levels during labor.

To test the hypothesis that prolactin (PRL) plays a role in the hormonal events of labor, serum PRL levels in 15 normal secundigravidas were measured on 2 occasions 10-15 days before delivery, at the onset of labor, at cervical dilatation of 5 and 10 cm, at the time of delivery, and on the first, second, and fifth days postpartum. The mean level of PRL was 163 ng/ml +/- 26 ng/ml at the onset of cervical dilatation; it typically decreased with the progress of labor, reaching a value of 140 ng/ml +/- 21 ng/ml at the time of delivery. The differences during the various stages of labor, however, were not found to be statistically significant. Postpartum values were significantly lower (P less than 0.01) on the fifth day after parturition. It is therefore unlikely that PRL is involved in or influenced by the hormonal interplay that occurs during labor.

Delivery, Obstetric↗