Effects of ethanol and ethanol withdrawal on nociception in rats

The effect of acute and chronic administration of ethanol and ethanol withdrawal on a radiant heat tail-flick assay of nociception was examined in rats. Acute administration of ethanol (2.0 g/kg, i.p.) produced peak antinociception (68% of maximum) by 30 min, and effects were gone by 120 min. Cumulative doses of ethanol (0.5-2.0 g/kg, i.p.) produced dose-dependent increases in latencies to 49% of maximum. During chronic administration, a liquid diet containing ethanol (6.5%) was given for 10 days. Tail-flick latencies were measured on day 0 (baseline), day 2, 4, 6, 8, and 10 of chronic ethanol and at 3, 6, 12, and 36 hr after removal of ethanol. To test for behavioral tolerance, both between- and within-group designs were used. In both between- and within-group experiments, the antinociceptive effects of chronic ethanol peaked by day 4 of exposure to the liquid diet, and tolerance developed by day 10. When the liquid diet was removed, hyperalgesia was detected at 6 and 12 hr after withdrawal, and was gone by 36 hr after withdrawal. When cumulative doses of ethanol (0.5-2.0 g/kg) were administered starting 12 hr after withdrawal, ethanol (0.5 g/kg) fully reversed the hyperalgesia induced by ethanol withdrawal, even though this dose was without antinociceptive effect in the absence of withdrawal. Higher doses of ethanol during ethanol withdrawal did not increase tail-flick latencies over baseline. In summary: (1) ethanol produces antinociception when administered acutely or chronically; (2) tolerance to the antinociceptive effects develops during chronic administration; (3) ethanol withdrawal induced hyperalgesia, which was reversed by ethanol; and (4) repeated testing did not produce behavioral tolerance.

Evidence for oxygenation-induced endothelin release from isolated lungs of chronically hypoxic rats

In lungs from chronically hypoxic (CH, 3 weeks at 10% inspired O2) rats, oxygenation (20% O2, 5% CO2, 75% N2; PO2 121 mmHg) of the perfusate increases pulmonary perfusion pressure (PPP) and lung weight (LW). Hypoxic perfusate (95% N2, 5% CO2; PO2 5.5 mmHg) had no effect on PPP in lungs from CH rats. Indomethacin and nitro-L-arginine (L-NOARG) augmented the oxygen-induced increase in PPP. In contrast, the free radical scavengers superoxide dismutase (SOD) plus catalase delayed the onset of oxygen-induced vasoconstriction, while the endothelin (ET)B receptor antagonist BQ788 inhibited it. The ET(A) receptor antagonist BQ123 did not affect the PPP changes. This suggests a role for endogenous endothelins and ET(B) receptors in mediating the oxygenation-induced pulmonary vasoconstriction. Indomethacin had no effect on oxygen-induced lung weight (LW) changes while BQ788 and L-NOARG reduced the LW increase. This evidence shows that ET(B) receptor activation and NO generation are involved in the LW changes. In conclusion, oxygenation of the perfusate in isolated lungs from CH rats leads to pulmonary vasoconstriction which involves endothelins and activation of ET(B) receptors. In addition, increased NO production associated with ET(B) receptor activation is the prime stimulus for observed LW increase.

Effects of tumour necrosis factor-alpha on left ventricular function in the rat isolated perfused heart: possible mechanisms for a decline in cardiac function

1. The cardiac depressant actions of TNF were investigated in the isolated perfused rat heart under constant flow (10 ml min(-1)) and constant pressure (70 mmHg) conditions, using a recirculating (50 ml) mode of perfusion. 2. Under constant flow conditions TNF (20 ng ml(-1)) caused an early (< 25 min) decrease in left ventricular developed pressure (LVDP), which was maintained for 90 min (LVDP after 90 min: control vs TNF; 110 +/- 4 vs 82 +/- 10 mmHg, P < 0.01). 3. The depression in cardiac function seen with TNF under constant flow conditions, was blocked by the ceramidase inhibitor N-oleoylethanolamine (NOE), 1 microM, (LVDP after 90 min: TNF vs TNF with NOE; 82 +/- 10 vs 11 +/- 5 mmHg, P < 0.05). 4. In hearts perfused at constant pressure, TNF caused a decrease in coronary flow rate (change in flow 20 min after TNF: control vs TNF; -3.0 +/- 0.9 vs -8.7 +/- 1.2 ml min(-1), P < 0.01). This was paralleled by a negative inotropic effect (change in LVDP 20 min after TNF: control vs TNF; -17 +/- 7 vs -46 +/- 6 mmHg, P < 0.01). The decline in function was more rapid and more severe than that seen under conditions of constant flow. 5. These data indicate that cardiac function can be disrupted by TNF on two levels, firstly via a direct, ceramidase dependant negative inotropic effect, and secondly via an indirect coronary vasoconstriction.

Lymphedema of the lower extremity as a complication of local burns

Lymphedema of an extremity is a rare complication of local burns, due to intact deep lymphatics. Here we present a case of delayed lymphedema of the foot, developing due to deep scarring after local burns.

Pharmacological treatment of alcoholism

1. Pharmacological treatments are effective as part of a treatment plan that includes substantial education, psychological therapy and social support. This paper reviews recent literature on animal models of and treatment for alcohol abuse under seven categories: agents to block craving or reduce alcohol intake, agents to induce aversion to alcohol, agents to treat acute alcohol withdrawal, agents to treat protracted alcohol withdrawal, agents to diminish drinking by treating associated psychiatric pathology, agents to decrease drinking by treating associated drug abuse, and agents to induce sobriety in intoxicated individuals. 2. The benzodiazepines provide safe and effective treatment for detoxification, although current research focuses on finding drugs with a smaller likelihood of dependence. As yet, there are no drugs that effectively reverse the intoxicating effects of alcohol. 3. Currently, only two major groups of drugs that are relatively safe have shown any effect at reducing alcohol consumption: aversives such as disulfiram, and opioid antagonists such as naltrexone. 4. Finally, it is important to customize therapy for each patient rather than putting everyone through a standard treatment plan, especially in regards to the use of antidepressant or antipsychotic medications. Tailoring the program to the patient's needs dramatically improves the outcome of therapy and reduces the risk of adverse effects.

A discriminative stimulus produced by 1-(3-chlorophenyl)-piperazine (mCPP) as a putative animal model of anxiety

1. This study compares behavioral responses to serotonergic (5HT) agonists and pentylenetetrazol (PTZ) in two behavioral paradigms used as animal models of anxiety. PTZ and mCPP were compared for behavioral effects in elevated plus-maze and interoceptive discriminative stimuli they produce. 2. PTZ is a known anxiogenic drug. The discriminative stimuli of mCPP were selected for comparison because this drug produces "anxiety" in human subjects and "anxiety-like" behaviors in rats, and is a potent agonist at 5HT1B/2C receptors and a partial agonist at 5HT2A receptors. 3. In rats trained to discriminate mCPP (1.4 mg/kg, training dose) from saline, PTZ substituted for the mCPP suggesting the "anxiety-like" properties of the mCPP stimulus. The mCPP stimulus was blocked in a dose-related manner by methysergide, a 5HT2A/2C antagonist but not by the anxiolytic diazepam. TFMPP (a 5HT agonist) and DOI (a 5HT2A/2C agonist) substituted for mCPP, but 1-NP (a 5HT1 agonist and 5HT2C/2A antagonist) did not. 4. In animals trained to discriminate PTZ (16 mg/kg) from saline, mCPP and DOI substituted for PTZ, while TFMPP and 1-NP do not. 5. In the elevated plus maze, time spent on the open arms was reduced by mCPP, DOI and PTZ but there was no significant dose effect of TFMPP, or 1-NP. 6. Methysergide blocked the "anxiety-like" behavior in the EPM. 7. These data suggest that the discriminative stimuli produced by mCPP are based upon its selective actions on 5HT receptors and their use in behavioral pharmacology may offer another tool in studying pharmacology of 5HT based anxiogenic and anxiolytic drugs.

Vitamin E status in protein energy malnutrition

Serum vitamin E and cholesterol concentrations were measured in 50 children with protein energy malnutrition (PEM) and results were compared with a group of 50 normal controls. Mean serum vitamin E concentration as well as vitamin E/cholesterol ratio were found to be reduced in children with PEM while their mean serum cholesterol level was not significantly different from the control group. Data suggest that the reduced levels of serum vitamin E in PEM may be a result of malnutrition per se.

Genes implicated in the pathogenesis of Alzheimer's disease

Both the early and late-onset Alzheimer's disease affect millions of people throughout the world. A number of molecules have been implicated in the pathogenesis of Alzheimer's disease. These include presenilin 1 and 2 (PS1 and PS2), a beta-amyloid peptide, and tau protein. Presenilin 1 and 2 genes implicated in the early-onset familial Alzheimer's disease have been cloned. Both PS1 and PS2 are integral membrane proteins and may function as receptors or channel proteins. Missense mutations in PS1 and PS2 genes have been found in families that cosegregate with early-onset Alzheimer's disease. Overexpression of the mutated PS1 gene produced amyloid plaques in the brain of transgenic mice. Secreted beta-amyloid protein similar to that in the senile plaques of Alzheimer's disease was found to be elevated in fibroblast media from subjects with PS1 or PS2 mutations. Transgenic mice which carried the mutant form of the beta-amyloid precursor protein gene expressed high concentrations of mutant copy of the gene and exhibited abundant amyloid plaques in the brain and memory loss. The mutated PS2 gene enhanced apoptotic activity. This enhanced apoptotic activity may accelerate the process of neurodegeneration leading to an earlier age in the onset of the disease. Identification of lesions in the molecules that are important in the Alzheimer's disease should allow developing therapeutic approaches for its treatment.

Tear lactoferrin concentration during postoperative ocular inflammation in cataract surgery

Tear lactoferrin concentration was measured by ELISA technique and followed in 30 patients undergoing cataract surgery. On the first day following surgery, there was a significant decrease in tear lactoferrin concentration followed by a gradual return to the initial values during the postoperative observation period of 7 days. There was an inverse linear relationship between tear lactoferrin concentration and the tear secretion rate measured by a modified Schirmer I test (1 min) suggesting a constant lactoferrin secretion by the tear glands. Since lactoferrin has known antibacterial and anti-inflammatory effects, the results may contribute to further understanding of the microbial vulnerability or resistance of the eye following surgical procedures.

Pathogenesis of Alzheimer's disease: current status on apolipoprotein E4 gene research

Alzheimer's disease (AD) affects millions of people throughout the world. The financial and emotional costs that are inflicted by this devastating disease are enormous. Genes responsible for the early-onset familial AD have been cloned and found to be membrane associated transport proteins. Evidence suggests that apolipoprotein E4 may be the risk factor for the late-onset form of the disease. Beta-amyloid and potassium channel dysfunction have also been implicated in the development of AD. Hyperphosphorylation of "tau" has been indicated for the generation of neurofibrillary tangles in the brains of Alzheimer's patients. Since apoE4 does not bind to "tau", apoE4 may contribute to the hyperphosphorylation of "tau" which may cause the formation of neurofibrillary tangles in AD patients. Molecular biology research on AD should help in the development of drugs for the prevention and treatment of the disease.

Effect of age and caloric intake on protein oxidation in different brain regions and on behavioral functions of the mouse

The objective of this study was to determine if oxidative stress/damage is a possible causal factor in the senescence-related loss of brain functions in the mouse. If such a relationship indeed existed, it was expected that oxidative protein damage would increase with age within regions of the brain associated with senescence-related functional loss, and that calorie restriction, an intervention which retards certain aspects of age-associated functional loss, would reverse such increases. Dietary restriction was found to retard age-associated decline of sensorimotor coordination and improve performance of aged mice on an avoidance learning problem. Protein carbonyl concentration, one measure of protein oxidation, increased from 8 to 27 months of age in most regions of the mouse brain, with the most notable increases occurring in the striatum and hippocampus, regions of the brain strongly implicated in age-associated functional loss. Age-associated loss of protein sulfhydryls was more uniform across brain regions and did not involve the hippocampus. Dietary restriction resulted in reversal of the age-associated regional trends in carbonyl and sulfhydryl concentration, with the largest changes occurring within the striatum. Cross over studies in aged calorie restricted and ad libitum fed mice indicated that lowering of carbonyl content by calorie restriction could be induced or reversed within a time frame of 3 to 6 weeks. These findings suggest that the beneficial effects of dietary restriction upon brain function and life span may depend upon its ability to acutely reduce steady-state levels of oxidative stress.

Investigation of the contributions of nitric oxide and prostaglandins to the actions of endothelins and sarafotoxin 6c in rat isolated perfused lungs

1. The aims of the study were to assess the contribution of prostaglandins and nitric oxide (NO) to the effects of endothelin (ETs) and sarafotoxin 6c (SX6c) in perfused rat lungs. This was carried out by using indomethacin, a cyclo-oxygenase inhibitor and NG-nitro-L-arginine (L-NOARG), a NO synthase inhibitor. Responses were studied under basal perfusion conditions and in other experiments after the elevation of vascular tone with the thromboxane-mimetic, U46619. The sub-types of ET receptors involved were characterized by use of ET receptor antagonists and cross-tachyphylaxis. 2. Pulmonary perfusion pressure (PPP), lung weight and pulmonary inflation pressure (PIP), were continuously recorded. Although L-NOARG (100 microM) did not alter basal parameters it markedly augmented the vasoconstriction and lung weight increases induced by ET-1 (50-400 pmol) or SX6C (25-200 pmol) while vasoconstrictor responses to phenylephrine were not affected by L-NOARG. 3. L-NOARG markedly potentiated the bronchoconstriction induced by ET-1 or SX6C whereas it had no effect on responses to carbachol. 4. When vascular tone was elevated, low doses (1.25-40 pmol) of ET-1, ET-3 and SX6C produced falls in PPP. The vasodilator potencies were SX6C > ET-1 = ET-3. The ETA receptor antagonist, BQ123, did not affect these depressor responses whereas the mixed ETA/ETB antagonist, bosentan, blocked them. 5. Indomethacin (10 microM) partially inhibited vasodilator response to ET-1, whereas it had no effect on SX6C-induced vasodilation. 6. L-NOARG plus indomethacin completely blocked ET-1 induced vasodilation, whereas responses to SX6C were blocked by L-NOARG alone. 7. Repeated injections of submaximal doses of ET-1 or SX6C caused tachyphylaxis to vasodilator responses. Subsequent injections of SX6C or ET-1 did not elicit depressor responses showing cross tachyphylaxis had occurred. 8. These findings indicate that under basal conditions the pulmonary vasoconstrictor, lung weight and bronchoconstrictor responses to ET-1 and SX6C are attenuated by evoked release of nitric oxide (NO). When vascular tone was elevated, lower doses of ETs and SX6C produced vasodilatation. These vasodilator responses are indirect, those to SX6C being mediated via NO production, whereas those to ET-1 involve both NO and prostanoid(s). Tachyphylaxis and ET antagonist experiments indicate that the same receptor subtype is involved in mediating the vasodilatation and that this is of the ETB type located on the endothelium. However the post-receptor vasodilator events triggered by ET-1 or SX6C appear to be different.

Age-related losses of cognitive function and motor skills in mice are associated with oxidative protein damage in the brain

The hypothesis that age-associated impairment of cognitive and motor functions is due to oxidative molecular damage was tested in the mouse. In a blind study, senescent mice (aged 22 months) were subjected to a battery of behavioral tests for motor and cognitive functions and subsequently assayed for oxidative molecular damage as assessed by protein carbonyl concentration in different regions of the brain. The degree of age-related impairment in each mouse was determined by comparison to a reference group of young mice (aged 4 months) tested concurrently on the behavioral battery. The age-related loss of ability to perform a spatial swim maze task was found to be positively correlated with oxidative molecular damage in the cerebral cortex, whereas age-related loss of motor coordination was correlated with oxidative molecular damage within the cerebellum. These results support the view that oxidative stress is a causal factor in brain senescence. Furthermore, the findings suggest that age-related declines of cognitive and motor performance progress independently, and involve oxidative molecular damage within different regions of the brain.

Effect of nitrendipine, nimodipine and nisoldipine on water and electrolytes excretion in rats

In water loaded (5 ml/100 g) unanesthetized rats. nitrendipine (NT), nimodipine (NM) and nisoldipine (NS) (5 mg/ kg, i.p.) caused significant (P < 0.01) increase in water and Na+ excretion. However, there was no significant increase in K+ excretion after NT, NM and NS administration. NS was more potent in increasing excretion of water load as compared to NT and NM. The glomerular filtration rate as assessed by creatinine clearance, was significantly (P < 0.01) increased in NT, NM and NS (5 mg/kg, i.p.) treated groups as compared to control. The mean creatinine clearance values after NT, NM and NS were 26.95 +/- 0.35, 22.11 +/- 0.72 and 28.13 +/- 0.95 respectively as compared to 22.19 +/- 0.51, 18.77 +/- 0.42 and 22.97 +/- 0.60 in corresponding control groups. The results of the study suggest that in addition to other effects, NT, NM and NS have a selective inhibitory effect on Na+ handling mechanisms in the nephron.

GM1 ganglioside reduces ethanol intoxication and the development of ethanol dependence

The monosialoganglioside, GM1, protects the nervous system against a variety of insults. In this study, we evaluated the protective properties of GM1 on ethanol intoxication and development of dependence. GM1 (20-40 mg/kg, IP) reduced the extent and duration of ataxia produced by ethanol (2 g/kg, IP, 15-95 min), and delayed the onset of loss and reduced the duration of the righting reflex (LORR) produced by ethanol (4.2 g/kg, IP). GM1 did not alter ethanol-induced hypothermia or the rate of ethanol clearance. Rather, GM1 increased the waking blood ethanol concentration. In animals fed a complete liquid diet containing 4.5% ethanol, concurrent administration of GM1 (40 mg/kg/day) blocked the tremors, hypolocomotion, and anxiety-like behavior associated with ethanol withdrawal. These findings demonstrate that GM1 reduces both ethanol's acute intoxication and the signs and symptoms of ethanol withdrawal by a mechanism not related to ethanol pharmacokinetics.

Actions of endothelins and sarafotoxin 6c in the rat isolated perfused lung

1. Endothelin (ET) receptors within the vasculature and airways were studied in a rat perfused lung model in which pulmonary perfusion pressure (PPP), pulmonary inflation pressure (PIP) and lung weight were continuously monitored. 2. The vascular potencies of ETs (ET-1 > ET-2 > ET-3) suggest an action via ETA receptors. This was confirmed by use of the antagonist, BQ123 (2 microM). The vasoconstrictor effects of sarafotoxin 6c (SX6C) also indicated the presence of ETB receptors. 3. Lung weight increases induced by ETs appeared to be a consequence of their vasoconstrictor potencies. The mixed ET receptor antagonist, bosentan (5 microM), markedly attenuated the responses of ET-1 and SX6C on PPP and lung weight, further implicating activation of both ETA and ETB receptors in these responses. 4. Endothelin-1 (ET-1) induced an accumulation of albumin-bound Evans blue dye in orthogradely perfused lungs. Retrograde perfusion attenuated the extravasation and increase in lung weight due to ET-1 but significantly augmented those induced by SX6C. 5. The bronchoconstrictor actions of ETs (ET-1 = ET-2 = ET-3) and SX6C suggest this is an ETB-mediated response. However SX6C was more potent than ETs and the dose-response curve was significantly steeper and achieved a higher maximum. 6. Indomethacin did not affect the vascular or bronchial responses to ET-1 or SX6C. 7. These findings indicate that rat pulmonary vasculature contains both ETA and ETB receptors. Retrograde perfusion suggests that ETB receptors are located arterially whereas ETA receptors are predominantly venous in distribution. Differences in the bronchoconstrictor potency of SX6C (compared to ETs) and the antagonism by bosentan may indicate ETB receptor heterogeneity in the airways.

The benzodiazepine receptor inverse agonist RO 15-3505 reverses recent memory deficits in aged mice

The benzodiazepine receptor partial inverse agonist RO 15-3505 was tested for its ability to improve impaired recent memory of aged mice. All mice successfully acquired a learning set for accurate identification of the correct arm of a T-maze and could perform with nearly 100% accuracy after 1-min delays. However, performance of the aged mice approached chance levels after 2-h delays. When injected just before testing on a series of 2-h retention tests, RO 15-3505 (from 2.5-3505 (from 2.5-10.0 mg/kg) resulted in a marked improvement of response accuracy. These results confirm the role of benzodiazepine receptor mechanisms in the modulation of memory processes, and suggest that the memory-facilitating effects RO 15-3505 or similar benzodiazepine receptor ligands may be generalized to aged rodents with impaired memory function.

Effect of age and caloric restriction on DNA oxidative damage in different tissues of C57BL/6 mice

The objective of this study was to explore the role of molecular oxidative damage and caloric intake in the aging process. The concentration of 8-hydroxydeoxyguanosine (8-OHdG), a product of DNA oxidation, was compared in five different tissues of mice (skeletal muscle, brain, heart, liver and kidney) as a function of age and in response to dietary restriction. A comparison of 8- and 27-month-old mice indicated that the age-related increase in 8-OHdG concentration was greater in skeletal muscle, brain and heart, which are primarily composed of long-lived, post-mitotic cells, than in liver and kidney, which consist of slow-dividing cells. Dietary restricted (DR) mice kept on 60% caloric intake as compared to the ad libitum-fed (AL) mice showed a lower concentration in 8-OHdG content in all the tissues compared to AL mice. The DR-related amelioration of DNA oxidative damage was greater in the post-mitotic tissues compared to those undergoing slow mitoses. Results support the hypothesis that oxidative damage to long-lived post-mitotic cells may be a key factor in the aging process.

Differential effects of agents on bronchial and vascular tone and lung weight in the rat isolated perfused lung

A ventilated perfused model of rat lung is described enabling continuous simultaneous measurement of pulmonary perfusion pressure (PPP), pulmonary inflation pressure (PIP) and lung weight. The preparation was stable for 2h before oedema formation commenced. Phenylephrine injected into the pulmonary artery produced selective increases in PPP (ED50 4.0 +/- 0.7 nmol, n = 5) without affecting airway tone or lung weight. Carbachol under basal perfusion conditions caused bronchoconstriction (ED50 4.25 +/- 0.4 nmol, n = 7) without affecting PPP and lung weight. Bradykinin (BK) caused increases in PPP (ED50 22 +/- 3 nmol, n = 8), lung weight and PIP (ED50 35.6 +/- 3.6 nmol, n = 8). Low doses of BK (25-50 nmol) caused increases in lung weight which were reversible. Higher doses (100-200 pmol) caused irreversible increases in lung weight which albumin-bound dye infusion showed were associated with albumin accumulation. Manipulation of venous outflow pressure revealed that the changes in lung weight induced by BK were potentially explicable as sequelae of vascular hydrostatic pressure changes possibly resulting from venoconstriction. It is concluded that this model is useful for studying drug actions on bronchial tone, pulmonary vasculature tone and vascular permeability.

Serum leucine aminopeptidase in head and neck cancer

Serum leucine aminopeptidase (LAP) activity was assayed in patients with head and neck cancer. The levels were found to be significantly higher than the controls. However, the rise in serum LAP was nearly the same in all patients studied, irrespective of the character or histopathology of the lesion but varied with respect to the site involved, i.e. from about 40 per cent in cancer of the hypopharynx to more than 100 per cent in cancer of the nasopharynx. Serum LAP activity was found to increase with the extent of the lymph node spread. After treatment the levels were found to be reduced.

Oxidative damage, mitochondrial oxidant generation and antioxidant defenses during aging and in response to food restriction in the mouse

This study was conducted in order to test the concept that oxidative damage is associated with aging and may be a factor in the modulation of life span in response to variations in caloric intake. Mice fed a diet that was 40% lower in calories (DR) than the ad libitum fed (AL) animals exhibited a 43% extension in average life span and a 61% prolongation in mortality rate doubling time. A comparison of AL and DR mice at 9, 17 and 23 months of age indicated that the protein carbonyl content in the brain, heart and kidney increased with age and was significantly greater in the AL than DR group in each organ at each of the three ages. Mitochondrial state 4 or resting respiratory rate increased with age in the AL, but not the DR group, and was also relatively higher in the former. The rates of mitochondrial superoxide and hydrogen peroxide generation increased with age and were higher in the AL than DR mice in all the three organs at each age. In contrast, there was no clear-cut overall pattern of age-related or dietary-related changes in antioxidant defenses provided by superoxide dismutase, catalase and glutathione peroxidase. Results suggest that mechanisms of aging and life span shortening by enhanced caloric intake are associated with oxidative damage arising from corresponding changes in mitochondrial oxidant production. Protein carbonyl content, and mitochondrial O2.- and H2O2 generation may act as indices of aging.