Twenty-four-hour fluid intake and renal handling of electrolytes after various doses of ethanol

Acute effects of ethanol on ingestive behavior in rats

The effects of acute ethanol administration on the ingestion of NaCl and food were assessed in adult rats subjected to 1-hr drinking and feeding tests 30 min after intraperitoneal administration of ethanol. Ethanol pretreatment did not induce spontaneous NaCl ingestion, but significantly potentiated angiotensin II-stimulated salt appetite, but not water intake, in a dose-dependent manner. Similarly, ethanol pretreatment significantly potentiated neuropeptide Y-stimulated food intake in nonfasted rats, but did not, by itself, cause spontaneous food ingestion. Ethanol pretreatment also significantly blunted pituitary secretion of oxytocin in response to multiple excitatory stimuli. Finally, administration of oxytocin intracerebroventricularly prevented the ethanol-induced potentiation of salt appetite elicited by angiotensin II. In view of our previous findings that central oxytocin secretion inhibits both NaCl and food intake, we propose that ethanol potentiates the ingestion of various solutes in rats, in part, by inhibiting brain-projecting oxytocinergic pathways concurrently with its well-known effects to inhibit pituitary oxytocin secretion.

Protracted metabolic acidosis: the impact of acute ethanol in hemorrhagic shock

The effects of acute ethanol administration on acid-base balance and hemodynamic parameters were studied in a canine model. Ten mongrel dogs, anesthetized and maintained on a volume ventilator, underwent splenic artery ligation 30 minutes prior to study. Group A (N = 5) served as controls. Thirty minutes after drug administration, the animals underwent a 20-cc/kg hemorrhage over 15 minutes. Thirty minutes postphlebotomy, resuscitation was performed with the same volume of homologous blood. Acid-base and hemodynamic parameters were monitored over 3.5 hours. Ethanol levels peaked 60 minutes following administration at 207 +/- 13 mg%. During the entire study, no differences were observed in heart rate, pulmonary capillary wedge pressure, systemic vascular resistance index, pO2, or pCO2, between the two groups. Following hemorrhage, statistically significant decreases in pH, mean arterial pressure (MAP), cardiac index (CI), and left ventricular stroke work index (LVSWI) developed in group A compared to controls. Maximal disparity developed in pH (7.21 +/- 0.05 to 7.33 +/- 0.02, P < 0.01), MAP (67 +/- 11 v 110 +/- 9 torr, P < 0.01), CI (1.69 +/- 0.24 compared to 2.72 +/- 0.19 L/min/M2, and LVSWI (18.7 +/- 1.2 compared to 44.9 +/- 4.8 gr-meter/M2/beat, P < 0.01) at 60, 45, 30, and 75 minutes postphlebotomy. In this study, ethanol directly or indirectly caused an increased metabolic acidosis and myocardial depression in the post-hemorrhage period.

Inappropriate vasopressin secretion in severe alcohol withdrawal

Forty-one male alcoholics suffering from alcohol withdrawal syndrome were investigated to assess the relationship between vasopressin (ADH), water homeostasis and alcohol withdrawal. During 10 d, we found a significant decrease in serum vasopressin, from 3.08 +/- 0.61 to 1.71 +/- 0.22 pg/nl. There were no concomitant changes in osmolality, so that a general dysregulatory state of vasopressin secretion during alcohol withdrawal cannot be assumed. Only patients with delirium tremens (8/41) had higher vasopressin levels despite lowered serum osmolalities. These findings support the hypothesis of an inappropriate rebound secretion of vasopressin in severe alcohol withdrawal. Furthermore, they may contribute to the pathogenesis of focal alcoholic brain damage, because rapid and/or profound changes in osmolality are suspected to cause circumscribed cerebral demyelinization.

Acute effect of ethanol on renal electrolyte excretion in rats

The purpose of this study was to investigate the renal handling of sodium and potassium in rats during an acute ethanol (ETOH) administration and to relate any observed changes to alterations in renin-aldosterone secretion. Eight male Wistar rats, 7 to 8 weeks of age, were injected intraperitoneally (IP) with 1.0 g/kg body wt. ETOH (15% v/v, 95% ETOH in saline, pH 6.98, osmolality 284 mOsm/kg). Blood ETOH levels were 159 +/- 16 (Mean +/- SEM) and 120 +/- 12 mg/dl, 10 and 30 min after the ETOH injection respectively (p less than 0.05). Control animals were given either an equal volume (1.77 ml/100 g body wt.) of 0.9% saline (n = 6) or 5% dextrose solution (n = 4) with similar pH and osmolality. Following ETOH administration blood pH, urine pH, plasma bicarbonate (HCO3) concentration declined significantly (p less than 0.01) while glomerular filtration rate (GFR) and hematocrit (Hct) remained unchanged (p = 0.1). Mean fractional sodium excretion (FENa), fractional potassium excretion (FEK), and osmolar clearance (Cosm) fell significantly despite an increase in plasma sodium (p less than 0.01), potassium (p less than 0.05) and osmolality concentrations (p less than 0.05). There was no significant change in plasma aldosterone concentration (PA) or plasma renin activity (PRA) following the ETOH administration. No difference in GFR, FENa, FEK, Cosm, blood pH, urine pH, plasma electrolytes, PA, or PRA was observed following the saline or dextrose injections. In conclusion, acute ETOH administration in rats alters renal sodium and potassium excretion independent of changes in GFR, PA, PRA or plasma volume as reflected by Hct.

Central Ca++-channel blockade reverses ethanol-induced poikilothermia in the rat

Two series of experiments were performed to determine the possible involvement of Ca++ channels in the thermolytic action of ethanol administered at a room temperature of 22 degrees C. In one group of 11 adult female Sprague-Dawley rats, stainless steel guide cannulae were implanted stereotaxically above the lateral cerebral ventricle. Prior to an experiment, a thermistor probe was inserted into the colon so that core temperature could be monitored continuously for up to six hours or until the temperature had returned to a previous baseline level. When the animal's body temperature had stabilized, a dose of 4.0 g/kg in a v/v solution of 20% ethanol was given by intragastric gavage. After the body temperature had declined by about 2.0 degrees C, ordinarily 30 min after ethanol administration, either control CSF or the vehicle plus one of four doses of verapamil (8.3, 25, 50 and 100 micrograms) was infused intracerebroventricularly (ICV) in a volume of 10 microliter. In a second group of 7 unoperated rats, either 4.0 g/kg ethanol or a physiological saline control solution was administered isovolumetrically by intragastric gavage; then, 30 min later, either 3.0 or 10.0 mg/kg verapamil was injected intraperitoneally. At an ambient temperature of 22 degrees C, ethanol gavage produced a significant decline in colonic temperature which was unaffected by physiological saline given by the same route. Although the CSF control vehicle was without effect, verapamil administered ICV attenuated the thermolytic action of ethanol in all doses tested; however, the lowest dose exerted its antagonist effect but with a longer latency. Conversely, when verapamil was given systemically, the hypothermic action of ethanol was significantly potentiated in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol in cardiomyopathic hamsters: Na and water excretion and righting response

This study examined the effects of ethanol and hereditary cardiomyopathy on sodium and water excretion by golden Syrian hamsters of both sexes. Ethanol (4 g/kg) or the isotonic saline vehicle were injected IP into 60-70-day-old hamsters of normal and cardiomyopathic (BIO 14.6) strains. Urine and blood were collected after 90 or 350 min in different groups. Cardiomyopathic hamsters more quickly lost their righting responses, eliminated ethanol more slowly, and had lower urine volume and sodium excretion than normal hamsters after ethanol injections. Plasma creatine kinase levels were normal in all animals tested, indicating no active skeletal or cardiac lesioning in the cardiomyopathic hamsters at the time of the experiment. Some factors which could contribute to the increased CNS and renal sensitivity to ethanol in cardiomyopathic hamsters include impaired ethanol metabolism, enhanced myocardial depression, and reduced atrial content of natriuretic peptides. The results do not owe to decompensated heart failure. Thus, the genetic mutation which causes skeletal and cardiac myopathy in these hamsters may also affect the metabolism and sensitivity to ethanol.

Chronic alcohol dependence and water-electrolyte status

Altered water-electrolyte status resulting from chronic alcohol dependence has been reported, although the nature of any such derangement is controversial. To illuminate this problem, four groups of rats were exposed chronically to schedule-induced polydipsia conditions with a single fluid available: 5% ethanol, 0.9% NaCl solution of 5% ethanol, 0.9% NaCl solution, or distilled water. An ad lib control group was also used. The water-electrolyte status of these groups was evaluated in two ways. First, the diuretic response to hydrochlorothiazide doses (8-12 mg/kg) was measured after 3.5 months of chronic polydipsia. Second, after approximately two additional months of polydipsia, extracellular fluid volume, as well as plasma volume and electrolytes were measured. Both alcohol-intake groups drank approximately 11.5 g ethanol/kg/day over the course of the experiment. Urinary volume response to the diuretic agent did not reveal that chronic ethanol led to either water retention or dehydration, even when extra NaCl intake was imposed chronically (NaCl-EtoH group). Animals that were overdrinking either water or the 0.9% NaCl solution had extracellular fluid volumes that were greater than the NaCl-EtOH-polydipsic group, but they were not significantly larger than ad lib controls. There were no significant differences with respect to serum electrolyte concentration measures among the groups. In conclusion, animals that drank ethanol chronically in a pattern known to produce physical dependence revealed no altered water-electrolyte status when evaluated by acute responses to a diuretic agent, a chronically-imposed extra NaCl load, or body fluid compartment and electrolyte concentration measures.

Role of alcohol in clinical nephrology

Different nephrological derangements are observed in severe alcoholics. Until now the direct toxicity of ethanol is only shown in the fetal alcohol syndrome with various malformations of the genitourinary tract. In the adult the kidney is often involved in the development, maintenance and counterregulation of complex electrolyte disturbances like phosphate and potassium hypoglycemia etc. The alcohol associated retention of urate, induced by hyperlactatemia and/or increased beta-hydroxybutyrate concentration is only rarely complicated by urate nephropathy. Alcohol intoxication (acute and chronic) predisposes to rhabdomyolysis with the risk of acute renal failure. There are some hints that chronic alcoholism with myopathy increases the vulnerability of the kidney for further toxic agents. In rats glycerol induced renal failure is enhanced by alcohol pretreatment. Finally, regular alcohol consumption raises the blood pressure, which per se is a risk factor for renal damage.

Alcoholic brain damage and neurological symptoms of alcohol withdrawal--manifestations of overhydration

Central nervous system damage is a major complication of alcohol abuse. Vitamin deficiency, particularly thiamine deficiency, has a role in producing pathological and psychological changes of alcoholic brain damage, but it is likely that alcohol has a direct toxic effect on the brain. It is proposed that neuropathological abnormalities seen in alcoholics, and also neurological symptoms during alcohol withdrawal, may reflect cerebral edema caused by alcohol. The neurological symptoms of alcohol withdrawal show a similarity to those seen in hyponatremia or water intoxication. It is suggested that alcoholics show overhydration particularly during withdrawal and that pathological changes in the alcoholic brain are related to cerebral edema. Cerebral edema in withdrawing alcoholics may be caused by inappropriate section of vasopressin (antidiuretic hormone).

Dietary salt and doca-salt treatments modify ethanol self-selection in rats

The effect of a salt supplemented diet on the voluntary intake of ethanol in male Wistar rats was examined in two experiments. In Experiment 1, the addition of 3% sodium chloride to the diet selectively increased the intake of moderately concentrated ethanol solutions (3 and 6%) while leaving the choice of a 12% solution unaffected. The choice and intake of water in the two former groups declined. In a second experiment four different groups of rats were offered the 3% salt supplemented diet in combination with daily injections of the synthetic salt-retaining mineralocorticoid desoxycorticosterone acetate (0.5, 1.5, and 6.0 mg/day). Ethanol intake again tended to increase in the 3 and 6% groups but in contrast to the results of Experiment 1 water intake also increased significantly. When desoxycorticosterone was administered without the salt supplemented diet, ethanol intake was significantly depressed while water intake increased. These findings indicate that a salt supplemented diet can significantly and selectively enhance the intake of moderately concentrated ethanol solutions and that while the addition of desoxycorticosterone injections to this diet has its effect primarily on water intake, these injections alone can also suppress ethanol intake indirectly by shifting the animals choice toward water and away from ethanol.

Effects of ethanol on thermoregulation

Clinical reports of accidental hypothermia in alcohol intoxicated individuals exposed to low ambient temperature ( Paton , 1983) have generally been borne out by experimental studies in healthy volunteers. Small doses of ethanol, given to human subjects at normal ambient temperature (Ta), have very little effect on body temperature but a combination of large dose, low Ta and vasodilatation provoked by strenuous exercise, causes a sharp fall in rectal temperature. In experimental animals, the use of relatively larger doses of alcohol and more extreme temperatures, both above and below the thermoneutral zone, has shown that the effect of ethanol is essentially poikilothermic, i.e. an impairment of adaptation to both heat and cold. This effect has been studied in greater detail, in relation to each of the basic thermoregulatory processes. Though small doses of alcohol may increase the metabolic rate under some circumstances, the most common effect at low Ta is inhibition of shivering and therefore reduction of thermogenesis. At the same time it tends to cause increased heat loss by cutaneous vasodilatation. This makes for a greater feeling of comfort in the cold exposed subjects but increases in rate of fall of core temperature. The combination of decreased thermogenesis and increased heat loss, despite falling body temperature, is suggestive of a lowering of the set-point of the thermoregulatory control mechanisms. Consistent with this is a slight increase in ventilatory heat loss after low doses of ethanol but larger doses cause respiratory depression, so that heat loss through the lungs is minor. However, at high Ta ethanol caused hyperthermia in experimental animals and shows enhanced lethality, so that impairment of thermoregulatory effector mechanisms seems to be at least as important as change in set-point. Studies of the effects of ethanol on electrophysiological activity of single neurons in the pre-optic area and anterior hypothalamus (POAH), biochemical activities of neuronal membranes, hypothalamic blood flow, conventional neurotransmitters, amino acid putative neurotransmitters, neuropeptides, prostaglandins and inorganic ions have all failed so far to yield a clear comprehensive picture of the mechanisms by which ethanol affects thermoregulation. In each case, contradictory evidence has been obtained concerning the consequences of ethanol administration, whether by oral, intraperitoneal, intravenous, intracerebroventricular, or direct local (POAH) route.(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in body temperature after administration of antipyretics, LSD, delta 9-THC, CNS depressants and stimulants, hormones, inorganic ions, gases, 2,4-DNP and miscellaneous agents

This survey concludes a series of complications of data from the literature, primarily published since 1965, on thermoregulatory effects of antipyretics in afebrile as well as in febrile subjects, LSD and other hallucinogens, cannabinoids, general CNS depressants, CNS stimulants including xanthines, hormones, inorganic ions, gases and fumes, 2,4-dinitrophenol and miscellaneous agents including capsaicin, cardiac glycosides, chemotherapeutic agents, cinchona alkaloids, cyclic nucleotides, cycloheximide, 2-deoxy-D-glucose, dimethylsulfoxide, insecticides, local anesthetics, poly I:poly C, spermidine and spermine, sugars, toxins and transport inhibitors. The information listed includes the species used, route of administration and dose of drug, the environmental temperature at which the experiments were performed, the number of tests, the direction and magnitude of body temperature change and remarks on the presence of special conditions such as age or lesions, or on the influence of other drugs, such as antagonists, on the response to the primary agents.

A silicone delivery system for producing binge and continuous ethanol intoxication in rats

A silicone delivery system for administering large quantities of ethanol (ETOH) to rats is described. When implanted subcutaneously and filled with 95% ETOH (v/v), lethal quantities can be administered within 5 days. Two different models are described: a rapid release thin-walled silicone pillow which can be filled with 95% ETOH for 3 hours daily so as to induce binge-like, transient high blood ETOH levels and motor impairment, and a thicker pillow which can be filled daily with 84% ETOH (v/v) so as to produce continuous ETOH administration. When different groups of rats administered similar amounts of ETOH using these two different regimens were compared, it was found that caloric intake (food + ETOH) and body weight were reduced in the Binge group whereas the Continuous group gained weight although their total caloric intake was similar to Controls. This delivery system can deliver appreciable amounts of ETOH to rats in the absence of gustatory stimulation and in two intake patterns which have been reported to occur in alcoholics.