Effect Of Ether Anesthesia Research Articles

The acute asymmetric effects of hemiovariectomy on testosterone secretion vary along the estrous cycle. The participation of the cholinergic system

The presence of asymmetry in the capacity of the left and right ovaries to secrete testosterone was analyzed by studying the effects of hemiovariectomy along the estrus cycle one hour after surgery. The effects of ether anesthesia on hormone serum levels were also analyzed.Bilateral ovariectomy and the extirpation of the left ovary performed on the day of proestrus resulted in significantly lower testosterone levels.Compared to the anesthetized group, the effects of perforating the peritoneum unilaterally varied according to the day of the estrous cycle and the side of the peritoneum surgery was performed on. Injecting atropine sulfate (ATR) to control or anesthetized rats on D1 resulted in a significant increase of testosterone serum levels.The effects of perforating the peritoneum on testosterone levels depended on the cholinergic innervation and varied along the estrous cycle. Blocking the cholinergic system before performing unilateral or bilateral ovariectomy had different effects depending on the day of the estrous cycle. Testosterone plasma levels increased significantly when surgery was performed on the day of diestrus and dropped when surgery was performed on proestrus. Similar effects were observed when the left adrenal was extirpated from animals with the cholinergic system blocked. The results presented herein support the hypothesis of asymmetry in the ovaries' abilities to secrete steroid hormones, and that the capacity to secrete testosterone varies along the estrous cycle.

Induction of Fos-like immunoreactivity in the basal ganglia by ether anaesthesia: effects of injections of muscimol in rostral versus caudal substantia nigra pars reticulata.

Exposing rats to ether anaesthesia for 20 min induced a massive expression of c- fos like (FL) immunoreactivity in specific regions of the brain, including the basal ganglia. This expression of FL immunoreactivity in the basal ganglia was successfully blocked by local injections of muscimol (GABA(A) agonist) in the substantia nigra (SN). This model was used to investigate our recent finding that inhibition of caudal SN pars reticulata (SNpr) with muscimol is more potent in suppressing the motor component of tonic seizures than comparable inhibition of the rostral part. Two experiments were carried out. In experiment I, the effects of ether anaesthesia on c- fos expression in the brain were investigated. Brain sections taken from untreated control rats and stained immunocytochemically with c- fos antibodies. The results showed no FL immunoreactivity in the SNpr, subthalamic nucleus (STN), entopeduncular nucleus (EPN) and globus pallidus (GP). However, a few scattered FL immunoreactive nuclei were observed in the caudate-putamen (CPu). In rats exposed to ether, numerous FL immunoreactive nuclei were detected in the SNpr, STN, EPN and GP. In the CPu, a slight increase in number of labelled nuclei was noted. In experiment II, rats were prepared with intracranial chronic cannulae through which the effects of muscimol (60 ng) injected unilaterally in either the rostral or caudal SNpr on c- fosexpression induced by ether were investigated. Injections in both sites caused remarkable suppression of the ether-induced c- fos throughout the ipsilateral SNpr; however, the rostral injection also inhibited the expression of c- fos in the STN, EPN and GP. The implications of these results for microinjection mapping studies of the SN are discussed.

The effects of ether anaesthesia on oxidative stress in rats — dose response

Rats, with and without overnight fasting, were anaesthetised for 5, 15 and 30 min with diethyl ether, killed immediately and total glutathione (total GS), thiobarbituric acid-reacting substances (TBAR), radical-trapping activity (RTA), total cytochrome P450 (CYP), and 7-ethoxyresorufin O-deethylase (CYP), 7-pentoxyresorufin O-dealkylase (CYP2B) and 4-nitrophenol hydroxylase (CYP2E1) activities of liver and kidney determined. Liver, after ether anaesthesia, but no fasting, showed 30–60% losses of total GS, RTA, and total CYP, after 5, 15 and 30 min of anaesthesia, while TBAR increased 10-, 20- and 35-fold for the same periods. Liver after ether anaesthesia and overnight fasting showed 50–85% losses of total GS, RTA and total CYP, for 0, 5, 15 and 30 min of anaesthesia, while TBAR increased 4-, 30-, 40- and 60-fold for the same periods of anaesthesia. Kidney changes were similar to those in liver. Liver CYP1 and CYP2B were decreased by 45% and 35%, respectively for 30 min of anaesthesia in fed rats, and by 80% and 30% respectively for 30 min of anaesthesia in fasted rats; in contrast, liver CYP2E1 was increased 30% by fasting alone and 70% by fasting plus 5 min of ether anaesthesia. Kidney CYP1 and CYP2B were similarly decreased by ether anaesthesia (70% and 50% respectively) in both fed and fasted rats, and CYP2E1 was similarly increased (by 40%–90% in fed and 30–110% in fasted rats). The decrease in tissue total GS, RTA, total CYP, CYP1 and CYP2B, and the increase in lipid peroxidation products (TBAR), are all considered to be due to generation of reactive oxygen species and oxidative stress, associated with the increase in CYP2E1 activity that results from both fasting and exposure to diethyl ether.

Effects of ether anaesthesia and fasting on various cytochromes P450 of rat liver and kidney

Fed and fasted, male, Wistar albino rats exposed to light ether anaesthesia and killed immediately or after 30 or 120 min recovery were compared with non-anaesthetized rats for changes in liver and kidney cytochrome P450 (CYP) activities. In fed rats, liver total CYP (nmol/mg protein) decreased by 30% immediately after ether, but was restored to normal levels after 30 min recovery; in fasted rats, liver total CYP increased by 20% by fasting alone, then decreased by 65% immediately after ether, and recovered to only 70% of control at 2 hr after ether. Rat liver cytochrome P4501A (CYP1A; 7-ethoxyresorufin O-deethylase or EROD activity) and cytochrome P4502B (CYP2B; 7-pentoxyresorufin O-dealkylase or PROD activity) were decreased after ether anaesthesia, similar to those for total CYP. In contrast, rat liver cytochrome P4502E1 (CYP2E1), determined by p-nitrophenol hydroxylation, increased by 40% by ether anaesthesia alone, 70% by fasting alone and 140% by ether plus fasting; these increases were confirmed by the CYP2E1-mediated activation of nitrosopyrrolidine and by immunoblot analysis using antibody to CYP2E1. In rat kidney, losses of total CYP, CYP1A and CYP2B, and increases of CYP2E1, induced by ether anaesthesia, were much more marked in fasted (90% loss in total CYP, 30% increase in CYP2E1) than in fed rats (slight loss in total cytochrome P450, 30% increase in CYP2E1). As maximum losses of total CYP in liver of fasted rats exposed to ether occurred at the time of maximum increase of CYP2E1 and maximum rate of generation of reactive oxygen species (ROS), it is suggested that the increase of CYP2E1, resulting from its stabilization by fasting and ether, leads to generation of ROS, increase in lipid peroxidation and consequent loss of total CYP, associated with the hepatic and renal necrosis seen in ether intoxication and surgical trauma.

Prolactin secretion and its response to stress during the estrous cycle of the rats.

Serum and pituitary prolactin (PRL) concentrations were measured during the estrous cycle of the rat with particular attention to the afternoons of the days of proestrus and estrus. Homogenizing machines, a Polytron and Sonifier, were used to extract PRL from the pituitary gland. The effects of ether anesthesia and restraint were also examined on the afternoons of both proestrus and estrus. The occurrence of a surge in PRL secretion during proestrus was confirmed with a peak at 1500 h, and this was accompanied by a decline in pituitary PRL content. A relatively high level of serum PRL was observed in the afternoon of estrus, during which time pituitary PRL content increased progressively. Ether anesthesia had no effect on the proestrus PRL surge, while restraint enhanced it. On the afternoon of estrus, restraint completely suppressed the rise in serum PRL, but ether anesthesia failed to suppress it completely. From these results, the following conclusions were drawn: 1) the PRL surge on the afternoon of proestrus occurs without synthesis of the hormone in the pituitary; 2) PRL secretion on the afternoon of estrus is accompanied by its synthesis in the gland; 3) the PRL response is distinct for each type of stress applied; and 4) PRL secretion is thus regulated by different mechanisms in proestrus and estrus.

Locomotor Activity in Drosophila Melanogaster

The effects of various experimental conditions on locomotor activity of adult Drosophila melanogaster flies of both sexes were measured in the locometer. This apparatus measures linear progression of flies and is based on the fractionating principle of mazes used for behavioural studies. Groups of approximately 100 flies are tested simultaneously but every individual fly is assigned a locomotor activity score. This score is positively correlated with open-field behaviour as measured in the Elens-Wattiaux-chamber. Strong lasting effects of ether anaesthesia were demonstrated. Other anaesthetics (c.q. CO 2 and N 2 ) did not show such profound effects. The effects of culturing conditions, density, age and sex were measured. The locometer proved to be useful for the investigations of the effects of different stimuli on the locomotory behaviour of fruitflies.

Effects of ether anesthesia and surface-induced hypothermia on regional blood flow

Regional blood flow and distribution of cardiac output (CO) were evaluated by the radioactive microsphere technique in seven rhesus monkeys prior to anesthesia, following the induction of deep ether anesthesia and throughout the cooling course during surface-induced hypothermia to temperatures of 20° C. As given, deep ether anesthesia alone significantly decreased OC 10 per cent to 15 per cent and output fraction (Qt) was decreased to the carcass, increased to the slanchnic circulation (although not statistically significant), and unchanged to other organs, while total vascular (TVR) and organ resistances were reduced. With the addition of cooling, CO progressively decreased. Individual organ Qt's, however, did not change from anesthetized parallel to the reduction of CO as cooling progressed. TVR and organ vascular resistances increased to levels in excess of 150 per cent of anesthetized precooling values, apparently as the result of viscosity rather than vascular changes.

Effect of ether on control of rate and depth of breathing in newborn rabbits.

The effect of ether anesthesia on Hering-Breuer inflation reflexes of newborn rabbit pups was investigated. Studies were done at a level of anesthesia at which an apneustic pattern of respiration is seen in vagotomized animals. The hypothesis that increase in vagal influence on respiratory frequency is accompanied by increase in influence on contractile force of the inspiratory muscles was tested. Two aspects of the Hering-Breuer reflex, breath duration and airway pressure developed with an elastic load, were evaluated simultaneously. This was done by performing airway occlusions at FRC--the results expressed as percent slowing on occlusion and as effective elastance (E'rs). The animals were studied with and without anesthesia, before and after vagotomy. Anesthesia resulted in a marked increase in vagal influence on inspiratory duration (34% increase) and on total breath duration (36% increase). In contrast E'rs was decreased (20%) after anesthesia whereas passive elastance was slightly increased. The vagal contribution to E'rs was essentially the same before and after anesthesia (36-38%). Thus ether anesthesia increases one aspect of the Hering-Breuer reflex without changing the other. These findings are likely due to depression of the central nervous system rather than due to peripheral effects of ether.

Effects of ether anesthesia on plasma prolactin sampling.

Bei mannlichen Ratten wurde das «Timing» der Prolactin-Stressreaktion gemessen und festgestellt, dass die Prolactin-Konzentration invariabel nach 2 min Ather-Stress ansteigt.

The nature of hypthalamo-neurohypophyseal neurosecretion in the rat. A study by light- and electron microscope autoradiography.

The nature of hypothalamo-neurohypophyseal neurosecretion was examined in the rat by means of intraventricular injections of tritiated amino acids. Quantitation of autoradiographs was used at the light microscope level to study the sites of synthesis of proteins and their time of arrival in the neural lobe. Electron microscope autoradiographs were used to study the labeling of neural lobe tissue. It was concluded that the great majority of the labeled material was translocated inside dense-cored granules and was probably composed mostly of neurophysins. The effect of ether anesthesia was also examined. It was found to remove the dense cores from about 20% of the granules in the neural lobe tissue, a process accompanied by the loss of most of their labeled material. The mechanism of the ether effect is discussed and compared to the normal secretion process.

The influence of short ether anesthesia on some liver enzyme activities in the rat.

Rats were anesthetized by ether inhalation for 4–5 min and sacrificed 1–48 h after anesthesia. From their liver homogenates, the activities of nine enzymes were determined. Activities of urate oxidase and arylsulfatase-A did not change significantly but arylsulfatase-B was slightly decreased. Malate dehydrogenase, arylsulfatase-B, and thiamine pyrophosphatase reached their highest and "malic enzymes" their lowest activities at the same time, 5 h after anesthesia. Alkaline phosphatase first decreased, later increased. Acid phosphatase and glucose-6-phosphatase activities decreased following ether anesthesia. Thesechanges in the enzyme activities generally agree and partly explain previously reported effects of ether anesthesia observed in the serum.

Effect of ether anesthesia on circulating insulin levels of rats on different goitrogens.

Present results show that ether anesthesia raises the mean plasma insulin levels and the variability of the individual data around the mean in rats under different experimental conditions. Previous results [6, 7] obtained in ether-anesthetized rats, showing that the plasma insulin levels of hypothyroid animals depends on the goitrogens used, and that there is a positive correlation between the individual thyroid weight and the plasma insulin levels, are confirmed in samples obtained without anesthesia.

The effects of altered endocrine states and of ether anaesthesia on mouse brain.

Abstract—The effects of ether anaesthesia on metabolites of mouse brain in altered endocrine states has been examined. Alloxan diabetic mice, with elevated levels of blood and brain glucose, exhibited changes in brain metabolites after ether anaesthesia that were comparable to those seen in normal animals. Sympathectomized and/or adrenalectomized mice had decreased levels of brain glucose. The percentage elevation of glucose in the brains of these animals under ether anaesthesia approximated to normal values, although the absolute cerebral levels were lower. Increases in glycogen in the brains of these animals were somewhat diminished. In none of the altered endocrine states were the changes in brain metabolites following ether anaesthesia eliminated.The activity of UDPglucose‐glycogen glucosyltransferase (UDPglucose: glycogen α‐4‐glucosyltransferasee, EC 2.4.1.11) in the mouse brain was measured in the absence and in the presence of glucose‐6‐P. Neither the total activity nor the percentage of the I form (measured in the absence of glucose‐6‐P) was altered by anaesthesia or by the endocrine state of the animal. The Michaelis constants with UDPglucose as substrate for the total and I forms were 0·36 mM and 1·0 mM, respectively. Considerable UDPglucose‐glycogen glucosyltransferase activity was observed in the absence of added glycogen primer. The observed increase in activity in the presence of added glucose‐6‐P was greater than would have been anticipated if the hexose phosphate were acting at only one site.

Effect of ether anesthesia on the glucuronic acid metabolism

Effect of ether anesthesia on the glucuronic acid metabolism

Further on the effects of ether anesthesia following one-trial discriminated avoidance learning

Ether anesthesia administered either 100 or 3160 sec after footshock significantly improved discriminated avoidance responding and reduced response latency only at the longer interval Ether anesthesia as a highly aversive stimulus accounts for the results better than the hypothesis that ether disrupts memory consolidation.

Reciprocal relationship of the lateral and ventromedial hypothalamus in the regulation of food intake

Abstract Spontaneous unit discharges (SUD) were recorded simultaneously from the VMH and lateral area (LH) of the hypothalamus in cats by glass capillary electrodes. Effects of ether anesthesia and electrical stimulation of the LH and VMH structures on the activity of the VMH and LH alone and the reciprocal relation between them were determined. Distributions of SUD frequencies and interspike intervals were determined, and after the stationarity of the time series had been established, auto and cross-correlation functions were calculated. Results on the intimate reciprocal relation between the VMH and LH fit the predictions of a stochastic model quite well and were also confirmed by changes in the EEG recorded from both hypothalamic regions in chronic twelve-hour food deprived animals.

Effects of ether anesthesia on myocardial metabolism in dogs.

Following the insertion of polyvinyl catheters into the aorta, pulmonary artery, and coronary sinus of dogs, metabolic studies of the heart were performed on intact, fasting animals. During ether anesthesia there was an increase in the arterial concentrations of glucose, lactate, and pyruvate, but a decrease in the concentration of unesterified fatty acids (UFA). Myocardial extraction of lactate, pyruvate, and UFA was a linear function of their arterial concentrations, but the extraction of glucose varied considerably. A rise in the myocardial RQ was associated with the increased extraction of carbohydrates. The decrease in the arterial concentration and myocardial extraction of UFA was thought to result from the greater availability of carbohydrate substrates. Ether anesthesia produced alterations in the pattern of myocardial metabolism, but did not seem to impair the over-all extraction of carbohydrates or UFA.

An assay of corticotrophin-releasing principles in hypothalamic lesioned rats.

ABSTRACT An assay of corticotrophin-releasing principles is described, using rats with lesions in the median eminence of the hypothalamus, 18 hours after electrocoagulation. In vitro steroidogenesis by adrenal glands was used as a parameter of pituitary-adrenal activity. The blocking effect of the lesion on the release of ACTH (corticotrophin) in response to stress was measured by the effect of ether anaesthesia on corticoid production in vitro of the left adrenal, whereas steroidogenesis of the right adrenal was used as an index of the corticotrophic effect of corticotrophin-releasing principles.

The mechanism of the electrocardiographic disorders in anaphylactic shock

Participation of the sympathetic nervous system in the cardiac changes occurring in anaphylactic shock was studied on 27 guinea pigs, and the effect of ether anesthesia, on 28 animals. Simultaneous recordings of the 3 standard ECG leads were taken as well as of respiration, blood pressure and motor reaction. The prevalence of sympathetic effects during shock was created by the administration of ephedrine, or atropine, or vagotomy. Nonspecific ECG changes, similar to the vagus-stimulation effect occurring during the intravenous booster injection of the antigen, developed both in the vagotomized and in the atropinized animals. Ventricular extrasystoles diminished in both groups of experiments. The ST vector experienced consecutive shifts to the left during the shock. The terminal disturbances of the ECG in the form of increasing positive values with rising ST complex and T wave, widening of the QT interval and disturbances of atrioventricular transmission developed simultaneously with the arrest of respiration in both vagotomized and atropinized animals. This excludes the leading role of the vagus nerve in the appearance of such disturbances. In 9 cases of shock against the background of anesthesia, a spontaneous regression of the terminal disturbances of the ECG occurred simultaneously with the resotration of respiration. The terminal ECG disturbances are evidently reflex in origin and are connected with diminished adaptational and trophic effecis of the sympathetic nervous system on the heart. The regression of the terminal changes is in keeping with the degree of restoration of these influences.

Effect of ether anesthesia on 17-hydroxycorticosteroid secretion in dogs

In dogs with previously cut dorsal spinal roots (T11-L3), adrenal venous blood was collected without anesthetic or pain. Ether was then inhaled for 30–60 minutes. During and after ether inhalation, adrenal venous blood was again collected and the plasma was analyzed for 17-hydroxycorticosteroids (17-OHCS). The mean preinhalation control secretion rate of 17-OHCS by one adrenal was 0.10 (0.06–0.20) µg/kg/min. During ether inhalation it increased to 0.34–1.2 µg/kg/min. Thirty to sixty minutes after the end of ether inhalation the secretion rate increased to a maximum of 0.79–1.8 µg/kg/min. and then decreased.