Postnatal Stress in Mice: Effects on Body Fat, Plasma Lipids, Glucose and Insulin

Mice pups were exposed to stressful stimuli everyday during the first 3 weeks of life. Body weight, food intake and spontaneous locomotor activity, triglycerides, cholesterol, phospholipids, glucose and insulin basal levels, as well as epididymal fat pad weight and its cell volume were measured in stressed and control animals. Results indicated that postnatal stressful manipulations induced an increase in body weight, epididymal fat pad weight and its cell volume, as well as in insulin, glucose, cholesterol and triglycerides plasma levels, at 4 months of age. No significant changes in food consumption, locomotor activity and phospholipids plasma levels were found. Present data suggest that early stressful manipulations may induce residual effects on lipid and glucid metabolism.

Pain and child: a translational hypothesis on the pathophysiology of a mild type-2 diabetes model

Pediatric pain management underwent many changes since the undertreatment of pain in children was reported in the literature in 1980. Increasing data also suggest that long-term behavioural effects can be observed in children, following pain episodes as early as in the neonatal period. Therefore, the knowledge about safe and effective management of pain in children should be applied with greater effectiveness into clinical practice. Other advances in the field include the findings of long-term residual behavioural and metabolic effects induced by pain experienced during the critical periods of development in laboratory animals. Recent data in laboratory animals and clinical data in children suggest that early repeated and/or severe pain and other stressful procedures applied in the perinatal periods may produce not only behavioral, but also important hormonal, immune and metabolic long-term effects. In this paper we shall report data on some metabolic conditions described in adult humans following disruption of hormonal-metabolic programming produced in the peri-natal period. Quite similar signs can be found between animal models and human conditions, most of them being connected with hypothalamus-pituitary-adrenal hormones (HPA) dysfunction. In addition, some signs in animal models, such as overweight and abdominal overweight are prevented by treatment with the μ- and δ-opioid receptor antagonist naloxone during the lactating period. This indicates that some long-term consequences following stress received during the early phases of life in mammals may be bound to the HPA system dysregulation, whereas others are bound to different (e,g., opioid) endogenous brain receptors and/or neuromediators alteration.

Formation of an adduct by clenbuterol, a beta-adrenoceptor agonist drug, and serum albumin in human saliva at the acidic pH of the stomach: evidence for an aryl radical-based process

Clenbuterol (CLB) is an antiasthmatic drug used also illegally as a lean muscle mass enhancer in both humans and animals. CLB and amine-related drugs in general are nitrosatable, thus raising concerns regarding possible genotoxic/carcinogenic activity. Oral administration of CLB raises the issue of its possible transformation by salivary nitrite at the acidic pH of gastric juice. In acidic human saliva CLB was rapidly transformed to the CLB arenediazonium ion. This suggests a reaction of CLB with salivary nitrite, as confirmed in aerobic HNO(2) solution by a drastic decrease in nitric oxide, nitrite, and nitrate. In human saliva, both glutathione and ascorbic acid were able to inhibit CLB arenediazonium formation and to react with preformed CLB arenediazonium. The effect of ascorbic acid is particularly pertinent because this vitamin is actively concentrated within the gastric juice. EPR spin trapping experiments showed that preformed CLB arenediazonium ion was reduced to the aryl radical by ascorbic acid, glutathione, and serum albumin, the major protein of saliva. As demonstrated by anti-CLB antibodies and MS, the CLB-albumin interaction leads to the formation of a covalent drug-protein adduct, with a preference for Tyr-rich regions. This study highlights the possible hazards associated with the use/abuse of this drug.

Taurine administration during lactation modifies hippocampal CA1 neurotransmission and behavioural programming in adult male mice

Taurine plays a role in neuronal development. In this study, we examined whether postnatal taurine administration influences the long-term consequences induced by mild neonatal stressors (10 min maternal deprivation plus sham injection, applied daily to neonatal mice up to 21 days). At 30 days of age stressed mice showed higher pain threshold both in the tail-flick--which measures mostly the spinal mechanisms of pain--and in the hot-plate test--which reflects mainly the supraspinal mechanisms of pain. The latter effect was prevented completely by neonatal taurine administration, while the tail-flick test was not affected, thus suggesting that spinal pain is not sensitive to taurine treatment. At 140 days of age, mice which were stressed during the neonatal period showed consistent decrease in immobility time in forced swimming test, and taurine did not influence this parameter. At the same age, the fear/anxiety axis, measured with elevated plus maze test, did not show any consistent changes. Electrophysiological experiments in brain slices obtained from adult mice showed that input-output curves in hippocampal CA1 were increased by taurine administration in lactation. Hence, neonatal administration of taurine might permanently modify the functioning of hippocampus, a brain area which is known to be crucial for learning and memory.

Nitric oxide is involved in the expression of neocortical spike-and-wave spindling episodes in DBA/2J mice

This study investigated the possible role of nitric oxide (NO) in the development of neocortical spike-and-wave spindling episodes (S&W) of DBA/2J mice. The administration of distilled water did not modify either the number or duration of S&W in DBA/2J mice during the whole recording period (240 min). L-N(G)-nitro arginine methyl ester (L-NAME) (3-300 microg/mouse, i.c.v.) dose-dependently reduced the S&W of DBA/2J mice. This effect appeared 30 min after drug administration and lasted for the duration of the recording period (240 min). In addition, L-NAME treatment did not induce significant alterations of stereotyped behaviour such as licking, sniffing, chewing or tremors of the head and body and behavioural excitability, whereas the electroencephalogram desynchronized pattern was also significantly reduced. By contrast D-N(G)-nitro arginine methyl ester at the same doses did not affect S&W of mice. The inhibitory effect of L-NAME on S&W of mice was dose-dependently reversed by L-arginine (L-ARG, 3-300 microg/mouse, i.c.v.) but not by D-arginine. Finally, glyceryl trinitrate on its own (3-300 microg/mouse, i.c.v.) significantly increased the S&W of mice and it was also able to reverse the inhibition on S&W of mice operated by L-NAME. These results provide evidence that NO may play a significant role in the development of brain excitability.

ALTEA: anomalous long term effects in astronauts. A probe on the influence of cosmic radiation and microgravity on the central nervous system during long flights

The ALTEA project participates to the quest for increasing the safety of manned space flights. It addresses the problems related to possible functional damage to neural cells and circuits due to particle radiation in space environment. Specifically it aims at studying the functionality of the astronauts' Central Nervous Systems (CNS) during long space flights and relating it to the peculiar environments in space, with a particular focus on the particle flux impinging in the head. The project is a large international and multidisciplinary collaboration. Competences in particle physics, neurophysiology, psychophysiology, electronics, space environment, data analyses will work together to construct the fully integrated vision electrophysiology and particle analyser system which is the core device of the project: an helmet-shaped multi-sensor device that will measure concurrently the dynamics of the functional status of the visual system and passage of each particle through the brain within a pre-determined energy window. ALTEA is scheduled to fly in the International Space Station in late 2002. One part of the multi-sensor device, one of the advanced silicon telescopes, will be launched in the ISS in early 2002 and serve as test for the final device and as discriminating dosimeter for the particle fluences within the ISS.

The ALTEA facility on the International Space Station

The ALTEA project studies the problems related to possible functional damage to the Central Nervous System (CNS) due to particle radiation in space environment. The project is a large international and multi-disciplinary collaboration. The ALTEA instrumentation is an helmet-shaped multi-sensor device that will measure concurrently the dynamics of the functional status of the visual system and the passage of each particle through the brain within a pre-determined energy window. ALTEA is scheduled to fly in the International Space Station in February 2003. One part of the multi-sensor device, one of the advanced silicon telescopes, will be launched in the ISS in early 2002 and serve as test for the final device and as discriminating dosimeter for the particle fluences within the ISS.

Purinoreceptors are involved in the control of acute morphine withdrawal

The effects exerted by P1 and P2 purinoceptor agonists and antagonists on the acute opiate withdrawal induced by morphine were investigated in vitro. Following a 4 min in vitro exposure to morphine, the guinea-pig isolated ileum exhibited a strong contracture after the addition of naloxone. The P1 purinoceptor agonist, adenosine, was able dose-dependently to reduce morphine withdrawal whereas alpha,beta-methylene ATP (APCPP), a P2 purinoceptor agonist, increased morphine withdrawal. Caffeine, a P1 purinoceptor antagonist, was able significantly and in a concentration dependent manner to increase morphine withdrawal whereas quinidine, a P2 receptor antagonist, reduced it. The results of our experiments indicate that both P1 and P2 purinoceptor agonists and antagonists are able to influence opiate withdrawal in vitro, suggesting an important functional interaction between the purinergic system and opioid withdrawal.

Dexamethasone blocking effects on mu- and delta-opioid-induced seizures involves kappa-opioid activity in the rabbit

Previous data indicate that intracerebroventricular administration of agonists for mu- and delta-opioid receptors induces limbic seizures in rats, but no data are reported in rabbits. We found that the mu- and delta-opioid peptides [D-Ala(2)-N,Me-Phe(4)-Gly(5)-ol]enkephalin (DAMGO), beta-endorphin and deltorphin II, induced EEG non-convulsive hippocampal seizures, and changes in hippocampal background EEG, physical parameters and overt behaviour after central administration. Dexamethasone pre-treatment prevented DAMGO-, deltorphin II- and beta-endorphin-induced seizures as well as changes in background EEG, physical parameters and overt behaviour induced by mu-opioid agonists. Dexamethasone antagonism on opioid action was blocked by pre-treatment with a protein synthesis inhibitor, cycloheximide or by the kappa-opioid antagonist nor-binaltorphimine. Our data suggest that dexamethasone influences opioid actions at mu- and delta-receptors via a protein synthesis mechanism involving kappa-opioid receptors.

Effects of cysteamine on nociception in mice

AIM

The present study was carried to study the effects of cysteamine on nociception in mice.

METHODS

The pain assays were the hot plate and the tail flick test.

RESULTS

When cysteamine, a drug well known as a somatostatin depletor, was administered 1 and 4 but not 24 h before the tests (hot plate, tail flick), the nociceptive threshold was elevated when the drug was administered at high doses (50 and 100 mg/kg) while at a lower dose (10 mg/kg), it was able to elevate the nociceptive threshold in the hot plate test only. In the hot plate as well the tail flick test cysteamine effects are reversed by naloxone administration and potentiated by morphine administration, whereas neither somatostatin nor cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr[Bzl], a reported somatostatin antagonist, changes cysteamine effects.

CONCLUSION

These results suggest that cysteamine effects on the nociceptive threshold in the hot plate and tail flick test may be mediated by cysteamine interference with the opioid system.

Arachidonic acid and its metabolites are involved in the expression of neocortical spike-and-wave spindling episodes in DBA/2J mice

This work was undertaken to study the effects of dexamethasone, indometacin and mifepristone plus dexamethasone on the neocortical spike-and-wave spindling episodes (S&W) in the electrocorticogram of DBA/2J mice. Our data indicate that both dexamethasone and indometacin (1, 10, 100 microg kg(-1), i.p.) reduced the S&W of DBA/2J mice. This effect appeared 30 min after drug administration and lasted for the duration of the recording period (240 min). Mifepristone, a glucocorticoid receptor antagonist (1, 10, 100 microg kg(-1), i.p.), injected 2 h before dexamethasone, totally blocked the steroid effect. These results indicate that both dexamethasone and indometacin significantly reduce the S&W of DBA/2J mice, suggesting a possible involvement of arachidonic acid and its metabolites in the development of brain excitability.

Clonidine-induced antinociception and locomotor hypoactivity are reduced by dexamethasone in mice

The effects of dexamethasone pretreatment on clonidine-induced antinociception and locomotor hypoactivity were investigated in mice. In the hot-plate and the tail-flick tests, dexamethasone administered intraperitoneally at a dose of 1 mg kg(-1), 30 or 60 min before clonidine, reduced clonidine antinociception in both tests and reduced clonidine-induced locomotor hypoactivity in the activity cage. When administered 15 min before clonidine, dexamethasone had no effect on clonidine antinociception. A higher dexamethasone dose (10 mg kg(-1)) induced the same effects observed at a dose of 1 mg kg(-1) in the hot-plate and the tail-flick tests, but the former dose had a stronger effect on locomotor hypoactivity. Dexamethasone (10 ng/mouse) administered intracerebroventricularly 30 min before clonidine was also able to reduce both clonidine-induced antinociception and locomotor hypoactivity. The protein synthesis inhibitor, cycloheximide, administered intraperitoneally at the dose of 10 mg kg(-1), 2 h before clonidine, was able to prevent dexamethasone effects on clonidine-induced antinociception. The glucocorticoid receptor antagonist RU-38486, administered intracerebroventricularly at the dose of 1 ng/mouse, was also able to block dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity, whereas both cycloheximide and RU-38486 per se did not influence pain sensitivity or locomotor activity. These results suggest that the dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity depend on the stimulating effects that dexamethasone exert, on the protein synthesis via the glucocorticoid receptor in the brain.

Clinical and pharmacological profile in a clenbuterol epidemic poisoning of contaminated beef meat in Italy

Long-acting beta adrenergic agonists, such as clenbuterol accumulate in the liver, but not meat of treated farm animals, and result in epidemic poisonings in consumers. We describe an outbreak of poisoning in 15 people, following the consumption of meat. Clinical symptoms (distal tremors, palpitations, headache, tachipnoea-dyspnoea, and also moderate hyperglycaemia, hypokalemia and leucocytosis) were seen in nine hospitalised patients, starting about 0.5-3 h after poisoning, and disappearing within 3-5 days later. Clenbuterol was found in the urine of all the symptomatic patients, at higher levels than pharmacokinetic computing (mean level 28 ng/ml, 36 h after ingestion), based on the levels found in the meat (1140-1480 ng/g edible tissue). Thus, epidemic poisoning can be produced following the consumption of contaminated meat. The need for a better definition of pharmaco- and toxico-kinetics, not only for drugs ingested as parent drug, but also when ingested as residues with animal tissues, is recommended.

Guinea-pigs treated with beta-endorphin fragments DTgammaE and DEgammaE exhibit reduced morphine inhibition of electrically-induced contractions

The effect exerted by two gamma-endorphin derivatives (DTgammaE and DEgammaE) was investigated on morphine-induced inhibition on the electrically contractions of guinea pig ileum in vitro. Morphine (1x10(-8)-5x10(-8)-1x10(-7) M) dose dependently and significantly reduced the E.C. of guinea pig ileum, IC50=6.5x10(-8) M (Confidence limits: 3.7x10(-8)-9.1x10(-8)). DTgammaE and DEgammaEper se (1x10(-6)-5x10(-6)-1x10(-5) M) did not modify significantly the E.C. of guinea pig ileum. Furthermore, DTgammaE or DEgammaE injection 10-30-60 min before morphine, did not affect the inhibitory effect of morphine on the E.C. of guinea pig ileum. By contrast, ilea from guinea-pigs treated for 4 days with DTgammaE or DEgammaE (1 mg/Kg/i.p.) resulted less sensitive to the inhibitory effect of morphine, IC50=8.3x10(-7) M (Confidence limits: 1.4x10(-6)-3.5x10(-7)) for DTgammaE and IC50=7.7x10(-7) M (Confidence limits: 2.7x10(-6)-8.7x10(-7)) for DEgammaE. Our results indicate that chronic treatment of guinea pigs with DTgammaE or DEgammaE induces a significant reduction of the inhibitory effect of morphine on the E.C. of guinea-pig ileum thus confirming an important functional interaction between gamma-endorphin derivatives and opioid system.

Effects of neonatal treatment with Tyr-MIF-1 and naloxone on the long-term body weight gain induced by repeated postnatal stressful stimuli

Stressful stimuli repeatedly applied during the first postnatal weeks can induce body weight gain in the mouse during adulthood. This effect can be prevented by injecting naloxone concomitantly with stress. The peptides belonging to the Tyr-MIF-1 family have a great modulating activity on numerous stress-induced phenomena. The aim of the present work was to compare the effect of repeated neonatal injections of Tyr-MIF-1 or naloxone on the long-term body weight gain induced by a stressing procedure applied daily during the first three weeks of life. The results indicate that although naloxone blocked the development of the stress-induced effects, Tyr-MIF-1 potentiated them.

Orphanin FQ reduces morphine-induced dopamine release in the nucleus accumbens: a microdialysis study in rats

The effects induced by orphanin FQ (OFQ) on morphine-induced dopamine (DA), 3,4-dihydroxyphenilacetic acid (DOPAC) and homovanillic acid (HVA) release in the nucleus accumbens were studied in rats by using microdialysis with electrochemical detection. Morphine administered intraperitoneally (i.p., 2, 5 and 10 mg/kg) dose-dependently increased DA and metabolites release in the nucleus accumbens. OFQ intracerebroventricularly (i.c.v.) administered at doses of 2, 5 and 10 nmol did not change DA and metabolites release in the nucleus accumbens. OFQ (10 nmol) administered i.c.v. 15 min before morphine (5 and 10 mg/kg, i.p.) significantly reduced morphine-induced DA and metabolites release in the nucleus accumbens. These effects suggest that OFQ may regulate the stimulant action linked to morphine-induced DA release in the nucleus accumbens.

Effects of cholinergic drugs on neocortical EEG and flash-visual evoked potentials in the mouse

The effects of single intraperitoneal injection of two cholinesterase inhibitors, physostigmine (PHY; 0.01, 0.025, 0.05, 0. 1, 0.2 mg/kg) and heptylphysostigmine (HEP; 0.5, 2, 6 mg/kg) on electroencephalographic (EEG) activity and flash visual evoked potentials (f-VEP) in the occipital cortex were compared in DBA/2 mice. EEG spectral analysis of awake periods showed that PHY at all doses and HEP at 2 mg/kg induced an increase of power in the 4.25- to 7-Hz frequency band. Furthermore, PHY at the higher doses and HEP at all doses induced a decrease of power in the 7.25- to 12-Hz frequency band, while the lower doses of PHY (0.01, 0.025 mg/kg) produced an increase of this band. EEG effects elicited by the two drugs were similar, when doses displaying analogous biochemical effects (acetylcholinesterase inhibition) were used (i.e. 0.01 and 0. 025 mg/kg of PHY versus 0.5 and 2 mg/kg of HEP). PHY and HEP induced similar changes in f-VEPs. Amplitudes of early and late components (P1N1, N1P2, P4N4 and particularly N1P3) were enhanced, while amplitudes of middle components were depressed after all doses. The peak latency measures were generally delayed, even though, after the lower doses, a trend to a latency reduction was evident in late components. This finding might indicate a possible effect on stimulus speed diffusion by 'low therapeutic' doses, analogous to the ones used in men. Our data show that both drugs are effective in modifying EEG and f-VEP parameters connected with brain cholinergic function, although in a very narrow dose range.

Adrenocorticotropin-related modulation of the human EEG and individual variability

During a 6-h period in resting conditions, the blood concentrations at rest of cortisol, glucose and the adrenocorticotropic hormone (ACTH) varied spontaneously within physiological ranges in eight healthy male volunteers (24.5+/-1.7 years), without pulsatile changes, correlation among variables, or indications of stress response. The power of the 6.5-14.0 Hz physiological 'alpha' rhythm of the electroencephalogram (EEG) proved inverted-U correlated with the ACTH concentration (with maximum power at 12-14 pmol/l ACTH) but was independent from the extent of ACTH change or from cortisol/glucose concentrations. Two subgroups of subjects with low/high EEG power values could be separated depending on ACTH concentration, with estimated cut-off at 7-8 pmol/l. A direct ACTH modulation of brain electrophysiology or common factors (e.g. the corticotropin-releasing hormone) pacing both ACTH and EEG are suggested and may account for individual EEG differences.

Clenbuterol residues in non-liver containing meat as a cause of collective food poisoning

beta 2-adrenergic agonists, particularly clenbuterol, are illegally used as growth promoters to obtain lean in meat. Their administration in feedlots can constitute a severe risk for animal welfare and exposes consumers to involuntary drug consumption at pharmacological active concentrations. Reported poisoning episodes have been associated with the consumption of beef liver where clenbuterol residues concentrate. In August 1996, 62 persons asked for medical help at the emergency rooms of 2 hospitals near the city of Caserta (Italy). Their clinical profile was characteristic of previously occurring clenbuterol intoxication, which reported superventricular extrasystoles and atrial fibrillation. All patients had non-liver beef meat consumption 10-30 min to 2-3 h before symptoms developed. An ELISA screening test specific for clenbuterol confirmed the drug's presence. Definitive confirmation of clenbuterol and determination of the drug content in meat samples were obtained by GC-MS, using 2 different derivatization. Concentrations in the meats ranged from 0.8 to 7.4 mg/kg. These analytical data provided evidence of the seriousness of the poisoning and helped the National Health System identify other possible misinterpreted cases. This case demonstrates that clenbuterol poisoning can also occur after consumption of beef meat other than liver.

Dexamethasone modifies the behavioral effects induced by clonidine in mice

The present study examines the influence of dexamethasone on behavioral effects induced by clonidine in mice. 2. The behavior elements considered were locomoter activity, rota rod, catalepsy and stereotyped behavior (rearing, grooming, social response test, crossing, smelling, washing face, scratching and bar holding). 3. Clonidine (0.1-0.5-1.0 mg/kg, IP) induced a significant reduction of all behavioral elements studied when compared to the saline treated group: the behavioral reduction was significant 10 min after administration and lasted for the entire recording period (120 min). 4. Dexamethasone (0.1-0.5-1.0 mg/kg, IP) per se did not induce significant changes in the behavior elements recorded. 5. Dexamethasone (0.1-0.5 mg/kg, IP) dod not affect behavioral effects induced by the 3 doses of clonidine, whereas the high dose (1 mg/kg) of the steroid significantly reduced its behavioral inhibition. 6. The results of the present study suggest that dexamethasone induces significant effects on clonidine-induced behavioral effects and that this may be related to an interference with the monoaminergic system.

Effects of low doses of physostigmine on avoidance learning and EEG in two strains of mice

The effects of the cholinomimetic drug, physostigmine (0, 0.01, 0.025, 0.05 and 0.1 mg/kg, i.p.), on shuttle-box avoidance learning and electroencephalographic (EEG) activity were investigated, in two separate studies, in mice belonging to the inbred C57BL/6 (C57) and DBA/2 (DBA) strains. The results of the behavioral investigation showed a consistent, significant enhancement of avoidance performance, on the whole of 5 daily training sessions, in C57 mice treated with the lowest dose (0.01 mg/kg) and in DBA mice treated with the highest doses (0.05 and 0.1 mg/kg) of the drug. Doses higher than 0.01 mg/kg, in C57 mice, and lower than 0.05 mg/kg, in DBA mice, had no significant effect. The avoidance improvements induced by physostigmine cannot be ascribed to general behavioral activation, since the doses that increased avoidance responses did not affect or even depressed spontaneous locomotor activity. The same doses of treatment which increased avoidance responding, also induced, in the same strains, consistent enhancement of 4-7 Hz (theta) EEG band power and decrease of 7-12 Hz (alpha) band power. Results suggest that the effects induced by physostigmine on the EEG and on the shuttle-box performance of mice are related to the same neurochemical systems, and are dependent upon the interaction of the dose with specific strain sensitivity.

Effect of naloxone on the long-term body weight gain induced by repeated postnatal stress in male mice

Stress during the early postnatal life of laboratory animals can induce body weight gain in adulthood. Exposure of mice to repeated postnatal stress has been shown to increase body weight some weeks after the recording of a hyposensitivity to thermal nociceptive stimulation. Since the increase in nociceptive threshold after repeated environmental manipulations can be interpreted as a behavioral index of stress-induced endogenous opioid release, the present experiment was designed to study whether the stress-induced body weight gain could be prevented by a chronic treatment with the opioid antagonist naloxone. Sixteen litters of CD-1 male mice were used. Treatments took place from day 2 to day 19 of postnatal life. As well as body weight we measured spontaneous motor activity and food and water consumption. Body length and epididymal fat pad weight were also measured, at the end of the experiment. Stress (i.e. a daily saline injection schedule) increased the rate of body weight gain and the epididymal fat pad weight; a daily injection schedule of naloxone did not induce these effects. No significant differences were evident among groups regarding body length, motor activity, or food and water intake. The data suggest that repeated postnatal saline injections may induce long-term modifications in body and epididymal fat weights and that these effects may be mediated by endogenous opioids.

Prescriptions for mesalazine and sulphasalazine: a prevalence estimate of patients treated for inflammatory bowel disease in Rome

BACKGROUND

Sulphasalazine and 5-amino salicyclic acid drugs are specifically indicated for the treatment of inflammatory bowel disease.

AIM

To use drug consumption by a given population as a marker to estimate the number of patients with inflammatory bowel disease.

METHODS

Prescriptions for sulphasalazine and mesalazine were identified for the 133000 inhabitants of a local health unit in Rome. Other prescriptions received by the patients, who were users of sulphasalazine or mesalazine, were also studied.

RESULTS

99465 patients received at least one prescription for any drug in 1991. Three hundred and seventy-six patients were prescribed sulphasalazine and/or mesalazine, an average of 3.8 prescriptions per patient. These patients were exposed more frequently than the general population to other drugs often used in inflammatory bowel disease treatment, for example, corticosteroids, anti-diarrhoeal drugs and intestinal anti-infectives. We identified that 258 of 100000 inhabitants were prescribed either sulphasalazine or mesalazine; 127 of 100000 inhabitants received full-dose treatment for at least 30 days, and 42.8 of 100000 inhabitants received prescriptions of either drug, also associated with systemic corticosteroids.

CONCLUSION

The consumption of drugs used specifically for inflammatory bowel disease may act as a marker for the prevalence of the condition in a community.

Dexamethasone reduced clonidine-induced hypoactivity in mice

Reduced clonidine anti-nociception in mice given low doses of dexamethasone has encouraged us to investigate the effects of dexamethasone pretreatment on locomotor hypoactivity, another example of clonidine-induced behaviour in mice. Dexamethasone administered intraperitoneally (0.1, 1.0, 10 mg kg-1) 30 min before clonidine reduced clonidine-induced locomotor hypoactivity in the activity cage to an extent which was dose-dependent. Dexamethasone administered centrally (10 ng/mouse) 30 min before clonidine was also able to reduce clonidine-induced locomotor hypoactivity. Cycloheximide administered at a dose of 10 mg kg-1 2 h before clonidine did not change the effects of clonidine but was able to prevent the effects of dexamethasone on clonidine-induced hypoactivity. The glucocorticoid receptor antagonist RU38486 administered centrally at the dose of 1 ng/mouse did not change the effects of clonidine, whereas it was able to block the effects of dexamethasone on clonidine-induced locomotor hypoactivity. These results suggest that the effects of dexamethasone on clonidine-induced locomotor hypoactivity depend on the stimulating effects that dexamethasone exerts on the protein synthesis via the glucocorticoid receptor in the brain.

Actinomycin D blocks the reducing effect of dexamethasone on amphetamine and cocaine hypermotility in mice

1. The present study examined a time-course effect of dexamethasone (DEX) on amphetamine and cocaine-induced hypermotility in mice and the influence of actinomycin D (dactinomycin), a protein synthesis inhibitor, on DEX effects. 2. Amphetamine (5 mg/kg IP) and cocaine (10 mg/kg IP) increased markedly the locomotor activity of mice, whereas DEX alone (0.1-1.0-10 mg/kg IP) did not modify the activity of control mice. 3. DEX pretreatment 0, 15, 30, 60 and 120 min before amphetamine or cocaine strongly decreased both amphetamine and cocaine effects, but no dose-related effect was observed. 4. The time-course study performed with DEX revealed differences in its reducing effect on cocaine and amphetamine hypermotility when the groups of animals treated with the steroid immediately before the cocaine (or amphetamine) injection were compared to those treated with the steroid later (15, 30, 60 and 120 min). 5. Furthermore, actinomycin D was able to block the reducing effect of DEX on both amphetamine and cocaine hypermotility. 6. Therefore, considering that the administration time of the steroid seems to be an important factor for reducing both cocaine and amphetamine hypermotility, and actinomycin D was able to block the reducing effect of the steroid, our study suggests that DEX exerts its reducing effect through a genomic activation.

Evolution of daytime quiet sleep components in early treated phenylketonuric infants

The maturational patterns of 'tracé alternant' (TA) and sleep spindles obtained from 16 early detected phenylketonuric (PKU) children during their first months of life were compared with others that were evaluated in recordings taken from 42 controls of the same age group. The TA maturation evolved significantly later in the PKU group than in the control group during the 5th-8th week (the TA score for the PKU group was 64% vs. 10% in the control group, P < 0.001). Afterwards, during the 9th-12th week the score for the PKU group was 27% vs. 0% in the controls (P < 0.002). The sleep spindle evolution score also matured significantly later in the PKU than the control group: the score was 31% in PKU children vs. 85% in controls for the 5th-8th week of age (P < 0.01), and it was 66% vs. 96% for the 9th-12th week (P < 0.02). After the 12th week, TA pattern could not be detected, and spindles reached complete maturation in the PKU children as well. Our results show a consistent delay in the maturation of TA and spindle scores in PKU children. This trend of delay is parallel to the plasma phenylalanine normalization, but not necessarily dependent only on it. In conclusion, we suggest that studies on the critical maturational periods of different sleep components (TA and sleep spindles) might provide a sensitive tool for early diagnosis of neurophysiological brain alterations during the first trimester of life in a population of children "at risk'.

Dexamethasone selective inhibition of acute opioid physical dependence in isolated tissues

The effect of dexamethasone on acute opiate withdrawal induced by mu, kappa and delta receptor agonists was investigated in vitro. After a 4-min in vitro exposure to morphine (less selective mu agonist), D-Ala2-N-methyl-Phe4-Gly5-ol)-enkephalin (DAGO; highly selective mu agonist) and trans(+/-)-3,4-dichloro-N-methyl-N-[2(1-pyrrolidynyl)cyclohexyl]- benzeneacetamide (U50-488H; highly selective kappa agonist) a strong contracture of guinea pig isolated ileum was observed after the addition of naloxone. This effect was also observed when rabbit isolated jejunum was pretreated with deltorphin (highly selective delta agonist). Dexamethasone treatment before or after the opioid agonists tested was capable of both preventing and reverting the naloxone-induced contracture after exposure to mu opiate agonists morphine and DAGO in a concentration- and time-dependent fashion. Also, the steroid reduced naloxone-induced contracture after the exposure to U50-488H only when injected before the kappa opiate agonist. Finally, it did not affect the naloxone contracture after exposure to deltorphin. Pretreatment with RU-38486, a glucocorticoid receptor antagonist, inhibited dexamethasone antagonism on responses to both mu and kappa agonists, whereas pretreatment with cycloheximide, a protein synthesis inhibitor, blocked only the antagonistic effects of dexamethasone on responses to the mu opioid agonists. Overall, these data indicate that dexamethasone induces significant effects on mu-mediated opiate with-drawal in vitro, which suggest an important functional interaction between corticosteroids and the opioid system primarily at the mu receptor level. The ability of RU-38486 and cycloheximide to block dexamethasone effects indicates that the steroid interference on mu-mediated withdrawal involves a protein synthesis-dependent mechanism via glucocorticoid receptor.

Relay activity of 17-beta oestradiol and diethylstilbestrol in a mouse-rat system

The biological activities of diethylstibestrol (DES) of 17 beta-oestradiol (17 beta E) were initially tested, based on the uterus enlargement induced by different doses given with food to immature female mice. In a second series of experiments, the drugs were given in higher doses per os to rats (relay animals) and after 24 h, the livers of the relay rats were removed. Parts of the livers were freeze-dried and were added (10% w/w) to the food of immature female mice, while the remainder underwent chemical analysis to determine the DES and 17 beta E content. When given directly to mice with their food, DES showed about six times more biological activity than 17 beta E. When given through the livers of relay rats, the biological activity of the livers from DES-and 17 beta E-treated relay rats was of the same magnitude. The content of 17 beta E in the livers of relay rats was 10-20 times higher than the DES. Such concentrations corresponded directly to the biological activity of livers. These data show that the bioavailability and the relative potency of xenobiotic drugs and natural hormones may be profoundly altered after passing through metabolic pathways, and may give useful indications for the evaluation of biological activity of residues and contaminants and their metabolites in the food.

Trihalomethanes in drinking water and cancer: risk assessment and integrated evaluation of available data, in animals and humans

In our study, we attempted to jointly consider THM concentration data collected from drinking waters and carcinogenic risk assessment derived from mathematical models commonly used in this field (multi-stage models for laboratory animal experimentation data, and 'unit risk' derived from the relative risk in the case of epidemiological data). In order to estimate the risks related to joint exposure to different THMs, in this study the risk additivity hypothesis is taken into account. Based on animal data for the various tumors, carcinogenic risk estimates for different THM combinations vary from 2.7 x 10(-7) to 4.6 x 10(-6) per micrograms/l in relation to different carcinogenic substances published in the literature or specifically calculated in this study. The carcinogenic risk parameters derived from experimental studies and from epidemiological data were substantially consistent. Our study uses also as an example some data on concentration levels of THMs for drinking water supplies in Sardinia. The area mean THM concentration values for each supply varied, for ground waters, from 8.1 to 13.6 micrograms/l and, for surface waters, from 52.8 to 168 micrograms/l. For the 1976-1989 period, bladder cancer standardized mortality rates in the water distribution system areas where the THMs were measured indicate values similar, but generally lower, than the national ones, except in the province of Cagliari where the values were not significantly different. The risk estimates derived from animal studies are of the same order of magnitude as the epidemiological data in literature.

Dexamethasone pretreatment reduces the psychomotor stimulant effects induced by cocaine and amphetamine in mice

1. The present study examined a comparison of the effect of DEX on psychomotor stimulant effects of cocaine and amphetamine in mice by using the locomotor activity test. 2. Cocaine (10 mg/kg/i.p.) and amphetamine (5 mg/kg/i.p.) increased markedly locomotor activity of mice whereas DEX per se (0.1-1.0-10 mg/kg/i.p.) did not modify the activity of control mice. 3. DEX pretreatment decreased the stimulating effects induced both by cocaine and amphetamine but no consistent dose-related effects were observed. 4. The results suggest that DEX may play an important role on the stimulating effects of cocaine and amphetamine and that it may be of some utility in the clinical management of psychostimulants abuse.

Reduced hippocampal CA1 Ca(2+)-induced long-term potentiation is associated with age-dependent impairment of spatial learning

Expression of Ca(2+)-induced CA1 long-term potentiation (LTP) was analysed in hippocampal slices obtained from (1) 3-month-old and (2) 18-20-month-old Sprague-Dawley rats selected for their performances in the Morris water maze task. In all slices, a transient (10 min) increase of extracellular Ca2+ concentration (4 mM) caused a long-lasting enhancement of potentials evoked by electrical stimulation of radiatum fibers. However, a significant difference was found in the degree of potentiation among groups. In particular, increases of the CA1 response amplitudes were significantly lower in old rats impaired in spatial learning than in young at 30 (P < 0.05), 60, 90 and 120 min (P < 0.01) after restoring the normal Ca2+ concentration. On the contrary, no differences were observed between young animals and the old ones with good performances in spatial learning. The data suggest that amplitude of CA1 Ca(2+)-induced LTP in old rats is related to spatial learning abilities.

Long-term changes induced by neonatal handling in the nociceptive threshold and body weight in mice

During the first 3 weeks of life, four litters of CD-1 male mice were daily handled (HA group) and four other litters were left undisturbed (UHA group). At 35 days of life, mice underwent the tail flick (TF) and hot plate (HP) tests to measure the baseline reaction to thermal nociceptive stimulation. At the age of 50, 80, and 140 days body weight was measured. At the last time point the epididymal fat pads (EFPs) were also taken and weighed. We found that, 16 days after the suspension of the manipulation. HA mice showed increased latencies to both nociceptive tests and, starting on day 80, they began to develop a significant increment in body weight. An increase was also evident in EFP weight of HA mice.

Dexamethasone reduces the behavioural effects induced by baclofen in mice

The present study examines the influence of dexamethasone on the behavioural effects induced by baclofen in mice. The behaviour elements considered were locomotor activity, motor co-ordination, catalepsy, stereotyped behaviour and antinociception. Baclofen (1.0-4.0-6.0 mg kg-1, i.p.) induced a significant reduction of all behavioural elements studied and an antinociceptive effect was recorded. Dexamethasone alone (0.1-0.5-1.0 mg kg-1, i.p.) did not induce significant changes in the behaviour elements considered. On the other hand, when the steroid was injected immediately before baclofen a significant reduction of baclofen's behavioural effects was found. Our results suggest a possible link between glucocorticoid and the GABA-ergic system.

Time-related antiepileptic effects of the synthetic glucocorticoid dexamethasone in rat hippocampal slices

The in vitro antiepileptic activity of the synthetic glucocorticoid dexamethasone (DEX) was tested in rat hippocampal slices on the CA1 epileptiform activity induced by sodium penicillin (PEN). Slice perfusion with 1 mM PEN produced within 60 min the development of a CA1 epileptiform bursting made up of an increase of the primary CA1 population spike followed by the appearance of secondary epileptiform population spikes. Slice perfusion with 100 microM DEX together with PEN (1 mM) partially prevented but did not block the expression of the CA1 epileptiform bursting as evidenced by a significant (P < 0.05) reduction of the duration of the bursting due to the epileptogenic agent. Slice perfusion with 50 microM DEX together with PEN (1 mM) failed to prevent or block the expression of the CA1 penicillin-induced epileptiform bursting. A 60 min slice pretreatment with 50-100 microM DEX followed by a slice perfusion with 50-100 microM DEX together with PEN (1 mM) prevented the expression of the CA1 epileptiform bursting. Cycloheximide (1 microM), a protein synthesis inhibitor, perfused together with DEX reverted the inhibitory effects of dexamethasone on the expression of the penicillin-induced CA1 epileptiform bursting. The results indicate that the synthetic glucocorticoid DEX presents concentration- and time-related in vitro antiepileptic effects. In addition, the data suggest that this inhibitory effect occurs via a protein synthesis-dependent mechanism.

Ultradian rhythms in the N1-P2 amplitude of the visual evoked potential in two inbred strains of mice: DBA/2J and C57BL/6

Ultradian rhythmicity has been showed in many behavioural parameters in animals as well as in humans. We investigated the existence of a Basic Rest-Activity Cycle (BRAC) rhythm in amplitude fluctuations of mice's visual evoked potential (VEP) primary component. Two inbred strains of mice, C57BL/6 and DBA/2J, were used to verify the influence of genetics on biological rhythm as well. Results revealed the existence of an evident rhythm in the parameter under study and confirm previous reports of a 20 min. BRAC in avoidance behavior in DBA mice. This rhythm shows similar period within each strain, but significatively different periods between strains. Observed periods are near to species-specific reported BRAC cycle. Genetic hypothesys is suggested to explain differences between strains in expression of ultradian rhythm.

Dexamethasone-induced selective inhibition of the central mu opioid receptor: functional in vivo and in vitro evidence in rodents

1. Endogenous corticosteroids and opioids are involved in many functions of the organism, including analgesia, cerebral excitability, stress and others. Therefore, we considered it important to gain information on the functional interaction between corticosteroids and specific opioid receptor subpopulations. 2. We have found that systemic administration (i.p.) of the potent synthetic corticosteroid, dexamethasone, reduced the antinociception induced by the highly selective mu agonist, DAMGO or by less selective mu agonists morphine and beta-endorphin administered i.c.v.. On the contrary dexamethasone exerted little or no influence on the antinociception induced by a delta 1 agonist, DPDPE and a delta 2 agonist deltorphin II. Dexamethasone potentiated the antinociception induced by the kappa agonist, U50,488. 3. In experiments performed in an in vitro model of cerebral excitability in the rat hippocampal slice, dexamethasone strongly prevented both the increase of the duration of the field potential recorded in CA1, and the appearance and number of additional population spikes induced by mu receptor agonists. 4. In both models pretreatment with cycloheximide, a protein synthesis inhibitor, prevented the antagonism by dexamethasone of responses to the mu opioid agonists. 5. Our data indicate that in the rodent brain there is an important functional interaction between the corticosteroid and the opioid systems at least at the mu receptor level, while delta and kappa receptors are modulated in different ways.

Visual, auditory, and somatosensorial evoked potentials in early and late treated adolescents with phenylketonuria

Pattern reversal visual, auditory, and somatosensorial evoked potentials were recorded in two groups of phenylketonuric (PKU) adolescents after protracted exposition to high concentrations of phenylalanine following diet discontinuation. The first group consisted of 11 early treated (before age 3 months) PKU patients (ET-PKU); the second group consisted of 11 late detected (after age 8 months), symptomatic, PKU subjects (LT-PKU). Despite the relevant lag between the two groups in mental development and neurological status, no clear-cut difference in evoked potentials could be detected. Only the wave I latency of the brainstem auditory evoked potentials (BAEPs) was significantly shorter in ET- versus LT-PKU children. The P100 latency, I-V interpeak latency (IPL), and I-III IPL seem to discriminate the less severe form of PKU (ET-PKU type 3) from the most severe forms, ET-PKU type 1 plus 2 and LT-PKU. No correlations were found between clinical, biochemical, and neurophysiological parameters. The present data suggest that evoked potentials technique is of limited sensitivity in detecting central nervous system (CNS) alterations in PKU adolescents after diet discontinuation.

Effect of des-tyrosine-gamma-endorphin on neocortical spike-and-wave spindling in DBA/2J mice

The effect of a beta-endorphin cleavage product devoid of opioid effects, des-tyrosine-gamma-endorphin (DT gamma E) on the neocortical spike-and-wave spindling episodes in the electrocorticogram (ECoG) of DBA/2J mice was studied. DT gamma E (0.01-1.0 mg/kg, i.p.) dose dependently reduced the spike-and-wave bursts duration. However, the low dose did not induce consistent modifications of the spike-and-wave bursts number while the dose of 0.1 and 1.0 mg/kg induced a progressive diminution. Furthermore, at all doses DT gamma E did not induce any alterations of the spike-and-wave bursts amplitude, frequency, and desynchronized activity when compared to the pre-drug period. These results indicate that this beta-endorphin fragment may affect brain excitability.

Dexamethasone influence on morphine-induced analgesia in outbred Swiss and inbred DBA/2J and C57BL/6 mice

1. The influence of dexamethasone on morphine analgesia in three different strains of mice (Swiss, DBA/2J and C57BL/6) was studied by using the tail flick test. 2. I.c.v. as well as i.p. injections of dexamethasone did not modify nociceptive response in all strains. 3. I.c.v. injection of dexamethasone significantly reduced morphine analgesia in Swiss mice whereas no effects were observed in DBA/2J and C57BL/6 mice. 4. In addition, i.p. injection of dexamethasone significantly reduced morphine analgesia in all three strains. 5. These results suggest that the use of different genetic strains may provide an useful approach for studying dexamethasone-morphine analgesia interaction.

Age and strain differences in rat place learning and hippocampal dentate gyrus frequency-potentiation

Induction of post-tetanic potentiation (PTP) and long-term potentiation (LTP) was analyzed in hippocampal slices obtained from (i) young (6 months old) rats of different strains (Sprague-Dawley, SD; spontaneously hypertensive rats, SHR; and Wistar-Kyoto, WKY), and (ii) from aged (20-24 months old) SD and Fischer 344 (F 344) rats, each group showing a different performance in the Morris maze test. After the application of an electrical tetanus (1 s, 100 Hz, 50 microA) in the stratum moleculare, a significant difference was found in the percent of induction of the dentate PTP in hippocampal slices obtained from rats of different strains and ages. In particular, the induction of the dentate PTP was significantly (P < 0.01) higher in slices obtained from young SD or spontaneously SHR rats, having the better performance in the Morris maze than in slices obtained from old SD or F 344 rats or young WKY rats which had poorer performances in the Morris maze. On the contrary, no significant differences were found in the percent of induction of the LTP in the dentate area of hippocampal slices obtained from rats of different strains and ages. Moreover, after the application of an electrical tetanus (1 s, 100 Hz, 50 microA) in the stratum radiatum, no significant differences were found in the percent of induction of both PTP and LTP in the CA1 area of hippocampal slices obtained from rats of different strains and ages.(ABSTRACT TRUNCATED AT 250 WORDS)

Subchronic treatment with fragments of beta-endorphin prevents electroencephalographic seizures and behavioral alterations induced by centrally administered beta-endorphin in the rabbit

The effects of some beta-endorphin fragments with neuroleptic-like properties, i.e., tau-endorphin, des-tyr1-tau-endorphin (DT tau E), desenkephalin-tau-endorphin (DE tau E), in comparison with the dopaminergic antagonist haloperidol,- were studied on the EEG and behavioral alterations induced by beta-endorphin in the rabbit. beta-Endorphin administered i.c.v. (5-30 nmol) induced EEG nonconvulsive limbic seizures as well as EEG background and behavioral alterations which were antagonized by naloxone administered i.v. (1-2 mg/kg). Haloperidol, tau-endorphin, DT tau E and DE tau E were unable to prevent beta-endorphin-induced alterations when injected in a single dose i.v. (25-50 micrograms/kg), 15 min before beta-endorphin. Subchronic i.v. administration of DT tau E or DE tau E (25 micrograms/kg/day) for 4 consecutive days prevented completely EEG limbic seizures as well as EEG background and behavioral alterations induced by i.c.v. beta-endorphin injected 15 min after the fourth dose; however, haloperidol (30 micrograms/kg/day) administered with the same schedule as DT tau E or DE tau E was able to prevent only EEG epileptiform and EEG background alterations induced by beta-endorphin. tau-Endorphin administered i.v. for 4 consecutive days (25 micrograms/kg/day) did not consistently influence any of the beta-endorphin effects. Our results show that DT tau E and DE tau E, which are devoid of opioid activity, exert a strong antagonism on ictal seizures as well as on other EEG alterations and behavioral alterations induced by beta-endorphin, and suggest that the antagonism shown by these drugs and by haloperidol on the EEG effects induced by beta-endorphin are exerted at least in part through an indirect action, i.e., an interaction with the dopaminergic system.

Phencyclidine reduces inherited neocortical spindling in DBA/2J mice

The role of phencyclidine (PCP) in the control of the spike-and-wave spindling episodes (S&W) which can be spontaneously recorded in the electrocorticogram (ECoG) of DBA/2J mice was investigated. PCP (0.1-0.5-1.0-5.0 mg/kg/i.p.) dose dependently reduced both S&W number and duration of DBA/2J mice. PCP reduction is significant 30-60 min after drug administration and lasts for the whole duration of the recording period (240 min). These results suggest that PCP may play an important regulatory role on brain excitability.

Effects induced by cysteamine on chemically-induced nociception in mice

The effects were investigated of cysteamine--a well known somatostatin depletor--on the pain induced by chemical stimuli in mice. Cysteamine injected intraperitoneally 4 h before the test at doses of 50 and 100 mg/kg reduced the second phase of the licking response which was induced by formalin injected into the hind paw. Furthermore, cysteamine administered at the doses of 10, 50 and 100 mg/kg reduced the writhing induced by acetic acid. Naloxone, yohimbine and CGP 35348 administered in cysteamine-pretreated animals were not able to change the cysteamine antinociceptive effects in the formalin test. Intrathecally injected somatostatin was able to revert the cysteamine antinociceptive effects in the second phase of the formalin test and in the writhing test, whereas intracerebroventricularly injected somatostatin reduced the antinociceptive effects induced by cysteamine in the second phase of the formalin test. Intrathecally injected cyclo(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr[Bzl])--a reported somatostatin antagonist--increased cysteamine antinociceptive effects in the second phase of the formalin test and in the writhing test. These results suggest that somatostatin is involved in the effects of cysteamine on the nociceptive threshold.

Dexamethasone and hormones related to the hypothalamic-pituitary-adrenal axis modulate inherited neocortical spindling in DBA/2J mice

The role of dexamethasone and hormones related to the hypothalamic-pituitary-adrenal (HPA) axis (corticotropin-releasing factor, adrenocorticotropic hormone, corticosterone) in the control of the spike-and-wave spindling episodes (S&W) which can be spontaneously recorded in the electrocorticogram (ECoG) of DBA/2J mice was investigated. Both dexamethasone and hormones related to the HPA axis consistently reduced the S&W in DBA/2J mice. Cycloheximide (a protein synthesis inhibitor) pretreatment significantly delayed the reducing effect of dexamethasone on the S&W in mice. After a transitory decrease, the glucocorticoid receptor antagonist RU-38486 induced a dramatic increase in the rate of the S&W episodes. In addition, mice treated with RU-38486 for 4 days showed a significant increase in the S&W 24 h after the 4th treatment. Our results indicate that dexamethasone as well as hormones related to the HPA axis are able to modulate the S&W in DBA/2J mice, suggesting that this effect may be bound to corticosteroid activity. The time lag (30-60 min) which is necessary for revealing the reducing influence of dexamethasone on the S&W in mice and the influence exerted by cycloheximide on dexamethasone activity support the hypothesis that the effect induced by dexamethasone may be at least in part dependent on genomic mechanisms.