Alcohol does not affect the trophic pancreatic effect of CCK and its plasma level in young rats.
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Animals↗
Biomedical subjects
M Papp
Publications and source records attributed to M Papp.
Subsensitivity to rewarding and locomotor stimulant effects of a dopamine agonist following chronic mild stress.
Chronic exposure to very mild unpredictable stress has previously been found to reduce or abolish the acquisition of place preference conditioning. In the present study, chronic mild stress was found to abolish the acquisition of preferences for a distinctive environment paired with systemic administration of amphetamine (0.5 mg/kg) or quinpirole (100-400 micrograms/kg) or with quinpirole (0.75 micrograms) administered bilaterally within the nucleus accumbens. The locomotor stimulant effects of quinpirole (100-400 micrograms/kg) were also attenuated in stressed animals. The result suggest that decreased sensitivity to reward following chronic mild stress results from a decreased sensitivity of dopamine D2 receptors within the nucleus accumbens.
Animals↗
Behavioural sensitization to a dopamine agonist is associated with reversal of stress-induced anhedonia.
Chronic exposure to very mild unpredictable stress (CMS) has previously been found to reduce the consumption of palatable sweet solutions and to impair place preference conditioning; evidence has been presented that these effects may reflect a dysfunction of the mesolimbic dopamine system. In the present study, rats were subjected to CMS for a total of 9 weeks. CMS reduced the consumption of a 1% sucrose solution. During weeks 6 and 7, animals received quinpirole (0-400 micrograms/kg) twice weekly. Both CMS-treated animals and controls showed sensitization to the locomotor stimulant effects of quinpirole. Subsequently, a sustained recovery of sucrose drinking was observed in quinpirole-treated stressed animals. During week 8, all animals received a single pair of place preference conditioning trials, in which quinpirole (200 micrograms/kg) was administered in a distinctive environment, and vehicle in a different environment. Non-stressed animals showed an increase in preference for the environment associated with quinpirole, as did stressed animals that had been sensitized to quinpirole, this effect was absent in untreated stressed animals. Finally, in week 9, acute administration of raclopride (150 micrograms/kg) was found to reverse the recovery of sucrose drinking in quinpirole-treated stressed animals, suggesting that these effects are mediated by an increase in dopamine function.
Animals↗
Influence of gastrointestinal (GI) hormones on suckling, gastric emptying and pancreatic trypsin content in the developing rat.
UNLABELLED: Aim of this study was to investigate how gastrointestinal hormones such as exogenous s.c. caerulein (6 micrograms/kg body weight), secretin (100 U/kg body weight), bombesin (20 micrograms/kg body weight, s.c.), CCK-8 (10 micrograms/kg body weight, i.p.), the CCK-A receptor antagonist L 364,718 (100 micrograms/kg body weight, i.p.), camostate (400 mg/kg body weight per os) which releases endogenous CCK and the coadministration of camostate with atropin (250 micrograms/kg body weight, s.c) or L 364,718 (1 mg/kg) influence milk intake from nipples, gastric emptying, and discharge of pancreatic trypsin content in 10-day-old rat pups. Saline-treated pups served as controls. The non-fasting Wistar rat pups of both sexes were used in littermate order. The suckling lasted for 30 and 45 min, respectively. One pup was used only once. After suckling the pups were decapitated, their stomach and pancreas were removed and weighed. The gastric food content was regarded as intake of milk and expressed as difference between the filled minus empty stomach. Pancreatic trypsin and protein content, plasma CCK level were measured. The exogenous agents did not influence gastric content. The investigated peptides decreased, L 364,718, however, increased the pancreatic trypsin/protein ratio. Camostate increased gastric content by 60% and decreased pancreatic trypsin/protein ratio vs saline by 90%. The gastric and pancreatic effects of camostate were not reversed by atropine or L 364,718. CONCLUSION: Exogenous and endogenous CCK seem not to influence milk intake while decrease pancreatic trypsin/protein ratio. However, endogenous CCK inhibit gastric emptying. The plasma CCK level was elevated due to the applied CCK-8 and camostate during the observed suckling period.
Animals↗
[Corrective possibilities by subcapital metatarsal osteotomy in the management of hallux valgus and metatarsus primus valgus].
The extent of correction achievable by inclined subcapital osteotomy of the metatarsus I. was studied in 100 cases of the deformation. The different angular values and dimensions were compared in the X-ray plates taken pre- and postoperatively and the clinical changes of the patients were evaluated on the basis of subjective complaints and objective symptoms. The angular limit values of the performability of osteotomy were determined. In deformations larger than the limit values wedge and half-wedge osteotomy, basisosteotomy, respectively, are the expedient methods.
Age Factors↗
Antidepressant-like effects of dopamine agonists in an animal model of depression.
Chronic exposure to mild unpredictable stress (CMS) has previously been found to cause an antidepressant-reversible decrease in the consumption of palatable sweet solutions. There is evidence that the effect of antidepressants in this model is mediated by an increase in transmission at dopamine (DA) synpases. The present study investigated whether another treatment known to increase the functional responsiveness of DA systems, intermittent administration of DA agonists, would have antidepressant-like effects. In three experiments in rats, CMS-induced decreases in sucrose consumption were reversed by three to four twice-weekly injections of quinpirole (100-200 micrograms/kg) or bromocriptine (2.5 mg/kg). The effects lasted for several weeks, and when they waned, could be reinstated by a single additional injection of quinpirole. As with tricyclic antidepressants, the effect of quinpirole was reversed by raclopride, administered acutely immediately prior to a sucrose consumption test; there were no changes in sucrose intake in nonstressed control animals. The results suggest that intermittent administration of DA agonists merits investigation as a novel strategy for the treatment of depression.
Animals↗
Reversal of stress-induced anhedonia by the atypical antidepressants, fluoxetine and maprotiline.
Chronic exposure to mild unpredictable stress has previously been found to depress the consumption of palatable sweet solutions. In the present study this effect was reversed by chronic (9 weeks) treatment with the atypical antidepressants, fluoxetine and maprotiline (5 mg/kg/day); the non-antidepressant chlordiazepoxide was ineffective. Stressed animals were also subsensitive to food reward in the place conditioning procedure; however, fluoxetine and maprotiline treated animals showed normal place preference conditioning. Acute pretreatment with raclopride (100 micrograms/kg) selectively reversed the recovery of sucrose drinking in antidepressant-treated stressed animals. These results extend previous reports of the efficacy of tricyclic antidepressants in this paradigm, and support the hypothesis of a dopaminergic mechanism of antidepressant action.
Animals↗
Additive effects of chronic treatment with antidepressant drugs and intermittent treatment with a dopamine agonist.
Locomotor activity in response to the D2/D3 agonist quinpirole was studied in male rats treated chronically (25-40 days) with imipramine, amitriptyline or mianserin (5 mg/kg/day). All three antidepressants potentiated the response to quinpirole. Repeated administration of quinpirole at 3-day intervals also caused a marked increase in the locomotor response to quinpirole. Imipramine-treated animals were more active than vehicle-treated animals on all quinpirole trials. Animals tested in the locomotor activity apparatus for the first time following their fifth quinpirole injection showed sensitization, but to a lesser extent than animals tested repeatedly under quinpirole. This context-independent sensitization was potentiated by all three antidepressants. We discuss the potential clinical relevance of these results.
Animals↗
Chronic mild stress-induced anhedonia: a realistic animal model of depression.
Chronic sequential administration of a variety of mild stressors causes a decrease in responsiveness to rewards in rats, which is reversed by chronic administration of antidepressant drugs. This paper reviews the validity of chronic mild stress-induced anhedonia as an animal model of depression, and the evidence that changes in hedonic responsiveness in this model are mediated by changes in the sensitivity of dopamine D2 receptors in the nucleus accumbens. The review opens with an analysis of the design features of animal models of depression, and ends with a brief account of other animal models of anhedonia.
Animals↗
Antiinflammatory effect of a protein kinase C inhibitor (K-252a) on the development of the dextran-induced paw edema in the rat (preliminary results).
The effect of a metabolite of Nocardiopsis sp. as a protein kinase C inhibitor from microbial origin was investigated on the onset and development of dextran-induced paw edema in the rat. It was published that this compound (K-252a) interferes with histamine release from mast cells, while dextran-induced paw and nose edema are induced by vasoactive agents, like histamine etc., released from the disrupted mast cells. The antiinflammatory effect of the K-252a is effectuated by the inhibition of protein kinase C. Groups of male Wistar rats with 180-200 g b.w. were used; each group consisted of 10-10 rats. The following groups were consisted: rats given orally DMSO (control), rats given 1 mg/kg, or 3 mg/kg b.w. of K-252a dissolved in DMSO and given p.o. one hour before dextran injection. Dextran (BDH Chem. LTD, molW: 200.000, England) was injected intraperitoneally in 10% solution, in a dose of one ml/100 g b.w. Volume of the hind leg was measured by a mercury plethysmometer. Time-sequence of the edema was followed. Increase in volume of hind leg paw was related to its 0-min volume in %. Results were analyzed by the Kruskal-Wallis-test. Edema of the legs and noses appeared in each of the control rats in one hour. The 1 mg/kg dose of K-252a retarded the appearance of the edema by 1 hour, the 3 mg/kg dose, however, prevented its onset for 4 hours.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Pancreatic cytoprotection: new approaches.
A brief report is given on the possible role of oxygen-derived free radicals and cholecystokinin in the pathogenesis of experimentally induced acute pancreatitis. Furthermore, use of scavengers (superoxide dismutase, catalase), CCK-receptor antagonists and somatostatin are discussed in the therapy of acute pancreatitis induced in animal models. It is suggested that both the term of direct pancreatic cytoprotection of the above-mentioned agents and the validity of the animal models used for induction of acute pancreatitis have to be reconsidered.
Animals↗
[Effect of somatostatin analogue on experimental pancreatic lesions and their sequelae].
The authors examined the effect of long acting somatostatin analogue (Sandostatin, Sandoz) on acute experimental pancreatitis and on the subsequent regeneration. Acute injury to the pancreas was produced by an intraductal intervention (ligature of the bile duct and intraductal injection of taurocholic acid) and by a metabolic route (supramaximal dose of caerulein by repeated subcutaneous injections). The effect of the drug on the acute injury was examined at 6 and 24 hours following the intervention and the effect on regeneration was examined on day 3 and 5 in all cases by determination of plasma enzyme levels and examination of the pancreatic tissue. Long acting somatostatin analogue did not prove to be effective in the serious acute pancreatitis produced by the intraductal intervention. However, in the acute phase of the caerulein induced pancreatitis, it had a beneficial effect as seen by it's ability to moderate the serum enzyme levels. During the examination of pancreatic regeneration was found that in caerulein induced pancreatitis the weight of the pancreas decreases due to atrophy and that this was not affected by long acting somatostatin analogue. As a matter of fact, the somatostatin counteracted the caerulein induced DNA increase, and therefore acted against the reactive hyperplasia. Therefore, the favorable effect of long acting somatostatin analogue is witnessed only in the caerulein induced acute injury but it does not accelerate the rate of pancreatic regeneration following injury. Due to this fact, protracted administration of this agent can not be rationalized.
Acute Disease↗
8-OH-DPAT-induced place preference and place aversion: effects of PCPA and dopamine antagonists.
Low doses of 8-OH-DPAT (62.5-250 micrograms/kg) were reinforcing in the place preference conditioning procedure, while a higher dose (1 mg/kg) supported a conditioned place aversion. The 5-HT synthesis inhibitor PCPA, and the DA antagonists pimozide and sulpiride, had no effect when administered alone, but abolished the 8-OH-DPAT-induced place preference. However, neither PCPA nor pimozide altered the 8-OH-DPAT-induced place aversion. The results are consistent with other evidence showing that 8-OH-DPAT acts through different mechanisms at low and high doses, and support the hypothesis that low doses of 8-OH-DPAT act through 5-HT neurons to disinhibit dopaminergic activity.
8-Hydroxy-2-(di-n-propylamino)tetralin↗
An animal model of anhedonia: attenuation of sucrose consumption and place preference conditioning by chronic unpredictable mild stress.
Chronic exposure to very mild unpredictable stress has previously been found to depress the consumption of, and preference for, highly palatable sweet solutions. The present study used the place conditioning procedure to investigate whether these effects result from a decreased sensitivity to reward. Rats were subjected to chronic mild unpredictable stress for a total of 4 weeks. During weeks 3 and 4, they received four training trials, in which rewards were presented in a distinctive environment, and four further non-rewarded trials in a different environment. The rewards used in different experiments were food pellets, dilute (0.7%) and concentrated (34%) sucrose solutions, and dl-amphetamine sulphate (0.5 and 1.0 mg/kg). In all experiments, non-stressed animals showed an increase in preference for the environment associated with reward; in stressed animals, these effects were abolished or greatly attenuated. Chronic unpredictable mild stress, which may be comparable in intensity to the difficulties people encounter in their daily lives, appears to cause a generalized decrease in sensitivity to rewards.
Amphetamine↗
Increase in plasma corticosterone level does not participate in increase of amylase content induced by lorglumide in the newborn rat pancreas.
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Amylases↗
Effect of lorglumide (CR-1409) on pancreatic secretory and trophic response to caerulein in newborn rats.
The authors investigated whether lorglumide a specific CCK-receptor antagonist affects the pancreatic actions of caerulein in female newborn Wistar rats. Pancreatic secretory response (expressed as the decrease in specific trypsin activity in the pancreas) was studied in 11-day-old rats following acute administration of saline (control), caerulein (0.3, 1, or 3 micrograms/kg s.c.) either without or with lorglumide (10 mg/kg s.c.). Lorglumide was given 15 min before caerulein. In chronic studies rats were treated 3x/day for 10 days from the day of birth (Day 1) with caerulein and lorglumide as above. On Day 11 the rats were decapitated and exsanguinated, their pancreas removed and analyzed. Acute administration of caerulein induced a dose-dependent depletion of specific trypsin activity from the pancreas and this was antagonized by lorglumide. Chronic treatment with each dose of the peptide increased total pancreatic trypsin content. Besides, the 3 micrograms/kg dose caused to increase pancreatic protein, DNA, and amylase content and to increase plasma corticosterone level. Chronic administration of lorglumide did not influence normal pancreatic growth, while it strongly inhibited the increase in trypsin content evoked by caerulein. However, lorglumide, given alone or in combination with caerulein, induced a significant increase in pancreatic amylase content without affecting plasma corticosterone level.
Amylases↗
A novel effect of MPTP: the selective suppression of paradoxical sleep in cats.
We studied the effect of MPTP on sleep-wakefulness cycle in cats. Five mg/kg n-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was administered i.p. for 5 consecutive days. Electrocorticographic, electrooculographic and electromyographic recordings were performed before (5 days), during (5 days) and after (14 days) the treatment. Total selective paradoxical sleep deprivation was observed from the first injection. This effect lasted 6-9 days after the last dose, while the relative amount of slow wave sleep increased. The Berg-Fourier analysis showed no significant change in the EEG power spectra of slow-wave sleep during the paradoxical sleep deprivation compared to control period. Recurrence of paradoxical sleep was parallel to the disappearance of the motor symptoms. Histopathological investigation showed neuronal loss mainly in the substantia nigra. Our present study suggests a complex behavioral effect of MPTP.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗