Ether Inhalation Research Articles

The importance of the hypothalamic lateral retrochiasmatic area in the control of adrenocorticotropin and thyrotropin secretion.

Anterolateral hypothalamic deafferentiation was made in rats to explore the importance of the neural pathways through the lateral retrochiasmatic area (RCAL) in the regulation of ACTH and TSH secretion. In rats with complete bilateral RCAL transection, pituitary-adrenal function was altered in the following respects compared to sham-operated controls. 1) Basal plasma ACTH, corticosterone (B), and adrenal weight were depressed. 2) Plasma ACTH and B elevation in response to 3-min ether inhalation were markedly decreased or abolished. 3) Insulin-induced hypoglycemia produced no or little plasma B elevation. 4) Lysine-vasopressin was significantly less effective in inducing pituitary-adrenal activation. Reductions in plasma ACTH and B concentrations and adrenal weight were correlated with the completeness of the RCAL transection. The plasma TSH concentration was lower in the deafferented rats than in the controls regardless of the completeness of the cut at the RCAL, indicating that the neural pathways traversing this area do not possess a critical importance for the regulation of TSH if the rest of the hypothalamus is deafferented anterolaterally. We conclude that intact neural connections between the medial basal hypothalamus and the central nervous system at the RCAL are essential for the maintenance of normal hypothalamic-pituitary-adrenal function.

Thiamine Whole Blood and Urinary Pharmacokinetics in Rats: Urethan-Induced Dose-Dependent Pharmacokinetics

The whole blood pharmacokinetics of thiamine after intravenous administration of thiamine hydrochloride (4, 12, and 36 mg/kg) to rats anesthetized continuously with ether (inhalation) or urethan (1 g/kg ip) were studied. Urinary excretion of thiamine after intravenous administration of thiamine hydrochloride to rats lightly anesthetized with ether was also investigated. At any particular dose, thiamine displayed apparent classical two-compartment model behavior in the time range studied. Under urethan anesthesia, thiamine displayed apparent dose-dependent kinetics as measured by the changes in the pharmacokinetic parameters, AUC, V d(area), t 0.5β and total body clearance, ClTB, with dose. However, when ether anesthesia was used, thiamine displayed dose-independent pharmacokinetic behavior. These results suggest that care should be taken in the interpretation of pharmacokinetic data obtained in anesthetized animals, particularly when urethan anesthesia is used.

イヌのエーテル麻酔時における血中麻酔薬濃度と脳波の変化

Electroencephalographic patterns observed during increasing depth anesthesia with thiopental sodium-ether, with ketamine hydrochloride-ether and with pentobarbital sodium were correlated with concentration of anesthetic agents in the blood. Analysis of electroencephalogram was made by histogram method.The results are as follows:1) Before anesthesia phase; Beta band of 20-25 Hz waves were shown 60-70% following alpha band was 30%.2) Induction phase; Delta band and theta band were increasing about 40% in place of beta band, but case of ketamine hydrochloride intervenous were increased beta band.3) Maintenance phase; 20-30% ether gas inhalation 5 minutes, a few beta band increased when this stage ether concentration in blood was about 60 mg/dl. Ether concentration in blood was over 70 mg/dl increasing delta band and theta band appearance ratio.4) Ether inhalation 30 minutes stage; Ether concentration in blood of 110 mg/dl when it was delta band only appearance ratio over about 50%.It was suggested that this method of analysis is adaptable to the quantitative study of contribution of each anesthetic agents when used simultaneously, provided that a significant change in EEG patterns and frequency band (delta, theta, alpha and beta waves bands), subject to classification, is produced by the agents considered.From the results of the present work, it was concluded that the changes EEG patterns were closely related to the depth of anesthesia and pharmacokinetics in the dog anesthetized with ether.

Delineation of the hypothalamic area controlling thyrotropin secretion in the rat.

Discrete midline hypothalamic lesions were made in male rats in the region of the paraventricular nuclei (PVN), ventromedial nuclei, and medial preoptic area (mPO) using modified Halasz C-shaped knives. In euthyroid rats, small lesions, including the PVN and little surrounding tissue, or large lesions, including portions of the dorsomedial nucleus, anterior hypothalamus, and preoptic area in addition to the PVN, caused a similar 60% drop in the plasma TSH concentration within 2 days which persisted for at least 3 weeks. PVN lesions also produced a significant decrease in plasma TSH in hypothyroid rats and diminished both the increase in plasma TSH in response to thyroidectomy and the decrease induced by ether inhalation. Ventromedial nuclei lesions preserving the PVN inconsistently decreased plasma TSH. mPO lesions anterior to the PVN induced a transient elevation of plasma TSH and GH only in hypothyroid rats. TRH-stimulated TSH secretion was not affected by any of the lesions. The results suggest: 1) the PVN and their immediate vicinity are of primary importance for maintaining a normal TSH response to the stimuli investigated, and 2) the mPO area tonically inhibits TSH secretion, presumably through its role in somatostatin secretion.

Hypothalamic multiunit activity correlates of the adrenocortical response to stress

The corticotropic response to stress was studied by means of multiple unit activity (MUA) recording from the adrenocorticotropic region of the hypothalamus, and plasma corticosterone (B) determination. MUA was permanently obtained and B was measured at 2, then 5 and 10 min intervals before and after neurogenic (electrical shocks) or systemic (ether inhalation) stress was applied. Experiments were made on steady unanesthetized, unrestrained thalamic pigeons. Post-stress alterations of MUA and B were closely in parallel, exhibiting a rapid and sustained increase in firing rate and shifting by 5–10 min, in corticosteronemia. Three successive and progressively decreasing peaks of MUA and B could be observed. Basal resting values were restored by approximately 90 min. Adrenocorticotropic responses to stress appear to be modulated through neural thalamic and/or rhombencephalic mechanisms.

Early opposition to obstetric anaesthesia.

AnaesthesiaVolume 36, Issue 5 p. 538-540 Free Access Early opposition to obstetric anaesthesia David Zuck, David Zuck Chase Farm Hospital, EnfieldSearch for more papers by this author David Zuck, David Zuck Chase Farm Hospital, EnfieldSearch for more papers by this author First published: May 1981 https://doi.org/10.1111/j.1365-2044.1981.tb10307.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 Zuck D. Simpson as a teacher—a student's notebook. British Journal of Anaesthesia 1976; 48: 1103– 11. 2 Cartwright FF. The development of modern surgery. New York : Crowell, 1968: 12. 3 Syme J. Principles of surgery. 3rd ed. London : Baillière, 1842. 4 Liston R. Elements of surgery. 2nd ed. London : Longman, Orme, Brown, Green & Longmans, 1840. 5 Simpson JY. Anaesthesia, or the employment of chloroform and ether in surgery, midwifery, etc. Philadelphia : Lindsay & Blakeston, 1849: 230– 48. 6 Shryock RH. The development of modern medicine. London : Gollancz, 1948: 104. 7 Flexner JT. Doctors on horseback. New York : Garden City Publishing Co., Inc., 1939: 110, 159. (See also Shryrock up cit: 14, for Elisha Bartlett on Meigs's idol, Benjamin Rush.). 8 Denham J. A report upon the use of chloroform in fifty-six cases of labour occurring in the Dublin Lying-In Hospital. Dublin : Hodges & Smith, 1849: 34. 9 Murphy EW. Chloroform in the practice of midwifery. London : Taylor & Walton, 1848: 4– 5. 10 Murphy EW. Further observations on chloroform in the practice of midwifery. London : Taylor & Walton, 1850: 40. 11 Houghton WE. The Victorian frame of mind 1830–1870. New Haven : Yale University Press, 1957. 12 Chitty S. The beast and the monk: a life of Charles Kingsley. London : Hodder & Stoughton, 1974. 13 Sulloway FJ. Freud, biologist of the mind. London : Andrè Deutsch, 1979: Fontana Paperbacks, 1980. 14 Simpson JY. Answer to the religious objections advanced against the employment of anaesthetic agents in midwifery and surgery. Edinburgh : Sutherland & Knox, 1847. 15 Simpson JY. Notes on the employment of the inhalation of sulphuric ether in the practice of midwifery. Monthly Journal of Medical Sciences 18471848; 7, 721– 8. (Also reprinted as a pamphlet, Edinburgh: Sutherland and Knox, 1847.). 16 Duns J. Memoir of Sir James Y Simpson, Bart. Edinburgh : Edmonston & Douglas, 1873: 215. Citing Literature Volume36, Issue5May 1981Pages 538-540 ReferencesRelatedInformation

Effects of paraventricular lesions on stimulated ACTH release and CRF in stalk-median eminence of the rat.

The effects of destroying the paraventricular nucleus (PVN) of the rat hypothalamus on pituitary-adrenal function were studied. Four days after PVN lesions were placed with a rotating knife, the basal plasma corticosterone level was normal, but the corticosterone response to electrical stimulation of the medial basal hypothalamus, surgical trauma, and ether-venesection stress was significantly inhibited. Four and 8 days after PVN lesioning and adrenalectomy, the basal plasma ACTH level was lower, and the rise of plasma ACTH level elicited by a 3-min ether inhalation was significantly smaller than in the adrenalectomized controls. Corticotropin-releasing factor (CRF) activity in the stalk-median eminence extracts from PVN-lesioned rats was significantly less than in the control extracts. The weight of the adrenals was decreased by both 2 and 4 wk after PVN destruction, and 2 wk after hemiadrenalectomy, the compensatory adrenal hypertrophy was inhibited. The plasma corticosterone response to ether-venesection stress was inhibited only temporarily because it returned to normal by the end of the 4th postoperative week. The results are consistent with the hypothesis that a substantial portion of CRF-containing fibers in the stalk-median eminence region either originate from or run though the PVN or its immediate vicinity.

Lack of correlation between hypothalamic serotonin and the ether-induced ACTH secretion in adrenalectomized rats.

The central serotonergic system was manipulated using a serotonin receptor antagonist (cyproheptadine), electrolytic lesioning of the raphe nuclei and neurochemical destruction of the serotonergic terminals in the hypothalamus. The effects of these interventions on ether-induced ACTH secretion were studied in adrenalectomized rats. Serotonin, norepinephrine and dopamine concentrations were measured in the medial basal hypothalamus (MBH) or in individual nuclei of the hypothalamus and of certain midbrain regions. Cyproheptadine pretreatment inhibited ether-induced ACTH hypersecretion in adrenalectomized animals. Neither the electrolytic lesions of the midbrain raphe nuclei, nor the neurotoxic destruction of the hypothalamic serotonergic terminals (by intraventricular administration of 5,6-dihydroxytryptamine) caused any alteration of stimulated ACTH secretion after ether inhalation and/or long-term corticoid deficiency. These results suggest a lack of correlation between the activity of the central serotonergic system and the ACTH releasing effect of ether-stress in adrenalectomized rats.

THE CAUSES OF AN OFFENSIVE BREATH IN CHILDREN, ACCORDING TO LOUIS STARR, A FOUNDER OF THE AMERICAN PEDIATRIC SOCIETY

In his ambitious An American Text-Book of Diseases by American Teachers (1894), Louis Starr (1849-1925), of Philadelphia, called attention to the importance of smelling the child's breath. In the 1890s, the paucity of what we now consider routine laboratory tests made the physician far more dependent on the use of the sense of smell when confronted with a sick child than is the case nowadays. Starr1 wrote: The breath may become sour, catarrhal, foetic, gangrenous, ammoniacal, and stercoraceous. Sour breath is present, in infants more especially, when there is gastric fermentation. Catarrhal breath has numerous shades of difference. In chronic catarrh of the pharynx there is a "heavy" odor, not noticeable far from the patient's face. It is always most marked during and after sleep. Should there be associated follicular tonsillitis, the breath, while still heavy, becomes extremely offensive, with a scent somewhat like that of decaying cheese, and is very penetrating. This odor, too, is worse after sleeping. At the onset of acute catarrh of the stomach the breath has a vinous odor, at other times it is sweetish, and again it has the same quality as after an inhalation of ether. Later in the attack it becomes sour or has the odor of sulphuretted hydrogen. What is known as a "feverish breath," has a heavy, sweetish smell. It is met with in diseases of high temperature; thus, it is very marked and rapid in appearance in scarlatina. Foetor of the breath is observed in its mildest form in such affections as aphthae and ulcerative stomatitis. It is better developed in ozaena and necrosis of the maxillary bones.

Adrenocrotical responses to systemic or neurogenic stress and to hypothalamic stimulation in chronically catheterized thalamic pigeons.

Thalamic and intact pigeons were equipped with a chronic arterial catheter and with a miniature electronic device for hypothalamic telestimulation. Chronic catheterization allowed for repetitive blood sampling in freely moving birds subjected to either systemic (ether inhalation) or neurogenic (electrical foot shocks) stress and to electrical stimulation of the hypothalamic corticotropic area. Corticosterone levels were determined by protein binding assay at 2-, then 5- and 10-min intervals, for 100 min. Basal and experimentally modified plasma corticosterone concentrations were not different in thalamic and intact pigeons. Corticosterone profile exhibited episodic increase including three peaks at 12, 35 and 60 min after stress application. Only the first peak of plasma corticosterone appeared after hypothalamic stimulation. It is suggested that extrahypothalamic neuronal networks are responsible for the long-lasting repetitive adrenocorticotropic response to stress, which are not involved in the single response to hypothalamic stimulation itself. Furthermore, such extrahypothalamic neuronal networks shoudl be located at the diencephalic or rhombencephalic level since hemispherectomized pigeons exhibited the same profile of stress-induced episodic hypercorticosteronemia as seen in intact birds.

Reevaluation of the pituitary-adrenal response to ether in rats with various cuts around the medial basal hypothalamus.

ACTH release elicited by ether inhalation or ethervenesection and measured by changes in plasma corticosterone level was studied in rats at various time intervals after placing a complete or an anterolateral cut around the medial basal hypothalamus (MBH). There was no rise in 'resting' plasma corticosterone after acceptable isolations and, in 5 out out of 6 series of experiments, the complete or long anterolateral cuts prevented the rise in plasma corticosterone normally induced by ether stress. In contrast, ethervenesection elicited a significant increment of plasma corticosterone when the basal region of the lateral retrochiasmatic area (RCAL) was not completely transected. Possible reasons why these experiments failed to confirm previous findings are discussed. These results support the hypothesis that corticoliberin-containing fibers enter the MBH from outside and that most of these fibers run through the RCAL on their way towards the neurohemal regions of the infundibulum.

Adrenocortical response to novelty stress in rats with dentate gyrus lesions.

Male rats exposed to a novel environment exhibited a marked rise of plasma corticosterone in response to the initial exposure. These animals showed a significant but not complete habituation of their adrenal response after 18 exposures. Following their first exposure to a novel environment, animals with bilateral lesions in the dentate gyrus of the hippocampus had plasma corticosterone concentrations which were significantly lower than those observed for the control animals. Whereas the control groups demonstrated a significant decrease in their adrenal response following 18 exposures (habituation), there was no decrease of the adrenocortical response to novelty stress within the dentate-lesioned group between trials 1 and 18. The effect of the dentate lesions appeared to be specific to the behavioral stress: dentate lesions failed to alter resting levels, or the animal's adrenal responses to laparotomy stress and ether inhalation.

Ether releases large amounts of prolactin from rat pituitaries previously "depleted" by short term suckling.

The effect of ether inhalation upon plasma PRL levels was assessed in lactating rats whose pituitary stores of the hormone first had been depleted by a short term (10-min) period of suckling in comparison with those whose PRL stores had not been depleted by prior suckling. Ether, unlike suckling or handling-decapitation stress, did not deplete pituitary PRL and caused only a small increase (36 to 52 ng/ml) in the plasma concentration of the hormone. However, when ether was given 10, 60, or 120 min after the plasma concentration had subsided from a prior 10-min period of suckling, the plasma concentration of PRL in each instance rose within 5--10 min to 200--250 ng/ml and was sustained at that level for the remainder of the 30-min exposure period. The amplitude and profile of the plasma PRL concentration after ether inhalation were similar to those obtained when a second suckling, rather than ether, was administered after the short term suckling. These data support the hypothesis that releasable PRL derives from depleted PRL and also indicate that, once it is formed, releasable PRL remains available for discharge into the circulation for a relatively long period of time.

Immunoreactive and biologically active somatostatin-like material in rat retina.

Somatostatin-like activity, as determined by radioimmunoassay and bioassay, is present in HCl extracts of rat retina. The concentrations of immunoreactive somatostatin are 612 +/- 43 (mean +/- SEM)pg per whole retina of 0.621 +/- 0.044 pg/microgram of protein in retinas from rats killed by decapitation, values which are not significantly different from those in retinas from rats killed by ether inhalation. The immunoreactive somatostatin was partially purified and concentrated by immunoaffinity chromatography. Both the crude retinal extracts and the immunoaffinity-purified immunoreactive somatostatin inhibited, in a dose-related manner, the release of rat growth hormone from dispersed rat anterior pituitary cells in culture. When the immunoaffinity-purified immunoreactive somotostatin was subjected to gel filtration chromatography, 96% of the recovered somatostatin eluted as a peak corresponding in position to that of synthetic somatostatin. Retinas from a group of rats with hereditary degeneration of the photoreceptor cells and another group of rats studied 1 year after transection of the optic nerves demonstrated an increased concentration of immunoreactive somatostatin compared to controls.

Possible role of brain norepinephrine in the hypothalamic hypophyseal adrenal system.

Intracisternal injection of bethanidine in rats decreased brain norepinephrine turnover without affecting its endogenous level, and increased both cardiac norepinephrine turnover and serum corticosterone level. A negative correlation was observed between brain norepinephrine turnover rate and serum corticosterone level. On the other hand, when cardiac norepinephrine turnover was suppressed by intraperitoneal injection of bethanidine, serum corticosterone did not change significantly. Next, ether inhalation was added after intracisternal injection of bethanidine. Then, serum corticosterone increased more even brain norepinephrine turnover was suppressed only slightly. These data may indicate that serum corticosterone increases by selective decrease in brain norepinephrine turnover via the humoral route; from the hypothalamus down to the adrenal cortex. Inversely, intracisternal injection of corticosterone increased brain norepinephrine turnover. These results suggest that brain norepinephrine may play an inhibitory role in the tonic regulation of CRF-ACTH secretion in the higher center than the hypothalamus and there may be a closed-loop feedback system between brain norepinephrine and serum corticosterone.

FUNDAMENTAL STUDIES OF ANESTHESIA ON EXPERIMENTAL INTESTINAL OBSTRUCTION IN DOGS

Experiments were performed to make comparison between the influence of Halothane (H-I) and Ether (E-I) inhalation anesthesia on experimental intestinal obstruction (upper occlusion) in dogs, at the same time intact Halothane (H-N) and Ether (E-N) inhalation anesthesia for control anesthesia were carried out.Comparison was made of clinical findings, blood pressure, blood gases and acid-base balance, blood components and body fluid.The results were as follows:1) After 96 hours of intestinal obstruction, decrease of body fluid and plasma chloride which were caused by a vomiting, at the same time increase of pulse rate, blood concentrate, hypotonia and a mild acidemia were recognized.2) In E-I group, delay of time of the laryngo-pharyngeal reflexes were observed, and 2 heads of E-I group died without a completely awaking.3) Body temperature, pulse rate and respiratory rate resulted similar effects in all groups (H-N, E-N, H-I, E-I) .4) Arterial blood pressure depressed in intestinal obstruction groups (H-I, E-I) .5) Halothane anesthesia groups (H-N, H-I) exhibited respiratory acidosis, and Ether anesthesia groups (E-N, E-I) showed mixed acidosis. Furthermore, intestinal obstruction groups (H-I, E-I) were more aggravating than control groups (H-N, E-N), particularity, E-I group maintained after the end of anesthesia.6) Ht, Hb, plasma electrolytes and osmotic pressure did not change in all groups (H-N, E-N, H-I, E-I) .7) Body fluid volume were not difference between H-I and E-I group.From these results, it is presumed that use of Halothane inhalation anesthesia was better than Ether inhalation anesthesia on intestinal obstruction in dogs.

Reflex effects of lung inflation and inhalation of halothane, ether, and ammonia.

Anesthetized dogs were perfused at constant pressure from an external oxygenator after removing their hearts. Systemic vascular resistance (SVR) and spontaneous breathing effors were monitored while the lungs were ventilated briefly at a low frequency with several tidal volumes and at a low volume with several frequencies. Inflation depressed respiratory activity and transiently lowered SVR to a minimum from which it spontaneously partially recovered. The transient and sustained SVR changes were directly related to peak inflating pressure, independent of the mode of ventilation. Pressurization of the sublaryngeal extrapulmonary airways and addition of ammonia to lung inspirate were without effect. Ventilation with 7% ether had no effect, but at 13% it occasionally increased respiratory activity. Ventilation with 7% halothane depressed SVR and stimulated respiration, whereas 13% caused vasodilation and apnea. The magnitudes of SVR responses to halothane and to inflation were uncorrelated. All effects of inflation and inhalants were eliminated by vagotomy. We condluded that the systemic vessels appear to respond to changes in respiratory minute volume; that this is brought about by intrapulmonary receptors, perhaps of more than one type; that two classical "irritants" have little effect in dogs; and that halothane has effects on breathing and SVR consistent with stimulation of J-receptors.

Pituitary Adrenocortical Response to Stress during the First Day of Post-Natal Life in the Rat

During the first hours of post-natal life, the newborn rat does not respond to ether stress by a rapid increase of ACTH secretion. Ether inhalation by 5- and 12-hour-old animals slightly but significantly increases plasma and adrenal corticosterone levels, but only 30 min after the onset of stress. At 1 day of age, adrenal response is established. The adrenal cortex of 5-hour-old animals responds normally to an intraperitoneal injection of 25 mU of ACTH. These results indicate that there is an absolute stress non-response period in newborn rats which is followed by a relative stress non-response period. The lack of response is not due to an organic block of the adrenal cortex, but could be due to the accumulation of elevated levels of corticosterone in the central nervous system.

Effects of chronic inhalation of dimethyl ether in the rat

Dimethyl ether (DME) is a colourless gas with an ethereal odour. It is used mainly as a liquid refrigerant and an aerosol dispersant. Little or no data exist on the toxicology of this material. In the present study, groups of male and female rats were exposed to 0.02%, 0.2% and 2% v/v of DME in air, 6 h/day, 5 days/week for 30 weeks. At the end of the study the high-dose level male rats showed a significant reduction on liver weight compared with the control group; this was accompanied by raising SGPT levels. In high-dose female rats there was no significant effect on liver weight but the SGPT levels were raised above control values. No histological abnormalities were observed in the liver or in any other organ.

Clover's portable regulating ether inhaler (1877)

The 100th anniversary of the first description of the 'portable regulating ether-inhaler' by Joseph T. Clover (1825-1882) is recalled. The importance of this piece of apparatus in the development of British anaesthesia is considered and the techniques of its use are outlined. Clover's personal portable inhaler is described and illustrated.