Propofol and ECT.
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Electroconvulsive Therapy↗
Biomedical subjects
T Torda
Publications and source records attributed to T Torda.
Increased beta 2-adrenoceptors in the superior cervical ganglia of genetically hypertensive rats.
[125I]Iodocyanopindolol binding sites were characterized by autoradiography in the superior cervical ganglia of Wistar-Kyoto (WKY) rats. A high concentration of (-)-[125I]iodocyanopindolol binding sites, characterized as beta-adrenoceptors by (-)-propranolol displacement, was distributed throughout the ganglia and in the postganglionic (internal carotid) nerve. ICI 118,551, a beta 2-selective antagonist, displaced more than 85% of the binding sites, whereas CGP 20712A, a beta 1-selective antagonist, displaced less than 10% of the binding sites, indicating that the beta-adrenoceptors were primarily of the beta 2-subtype. Emulsion autoradiography demonstrated that at least part of the binding sites were associated with principal ganglion cells. Unilateral deafferentation did not modify the number of binding sites in the superior cervical ganglia of WKY or spontaneously hypertensive rat (SHR). These results suggest that at least part of these receptors may correspond to prejunctional beta 2-adrenoceptors originated in principal ganglion cells. The concentration of beta 2-receptors was increased in the superior cervical ganglia of young and adult SHR when compared to age-matched WKY rats (49% and 39%, respectively). There were no differences in beta 2-adrenoceptor number in the stellate ganglia of young and adult WKY and SHR. These results suggest that beta 2-adrenoceptor stimulation may be selectively enhanced in some peripheral sympathetic ganglia in SHR and this could play a role in the development and maintenance of the increased sympathetic activity in this strain.
Adrenergic beta-Antagonists↗
A graded combination regimen for maintenance of gastric pH above 3.5 in critically ill patients.
Prophylaxis of acute upper gastrointestinal bleeding by control of gastric pH has been widely advocated for intensive care patients. H2-blockers and antacids have been used and demonstrated to be incompletely effective at maintaining gastric pH above 4. A study of 100 patients measured the efficacy of two-hourly gastric pH measurement and titrated therapy consisting of five levels: 1. no therapy 2. ranitidine 50 mg 8 hourly intravenously 3. ranitidine plus Mylanta 30 ml 2 hourly by nasogastric tube 4. ranitidine plus Mylanta 60 ml 2 hourly and 5. ranitidine 100 mg 8 hourly intravenously plus Mylanta II 60 ml 2 hourly. The level of treatment required by proportions of the total study group were (1) 15%, (2) 71%, (3) 96%, (4) 100%. Head-injured and intubated patients generally fell in the more resistant group while patients having had major elective surgery required lower levels of therapy. If control of gastric pH is to be uniformly achieved, a technique of titrated therapy based on gastric pH measurements is supported as cheaper and more effective than other standardised treatment regimens.
Adult↗
Propofol as an anaesthetic agent for ECT: effect on outcome and length of course.
Recent reports of reduced seizure duration with ECT under propofol anaesthesia have led to concerns that propofol may diminish the efficacy of this treatment. To investigate the effect of propofol on the response to ECT, we reviewed records of 66 patients with primary depression treated with ECT, 37 of whom had been assessed prospectively with pre- and post-ECT Hamilton and Zung depression severity ratings. Despite demonstrating that the individual seizure duration was significantly reduced with propofol compared to thiopentone we found no evidence of reduced ECT efficacy with propofol. Courses under propofol anaesthesia were on an average two treatments longer than with thiopentone. Although this difference was not statistically significant this may have been due to a type II error. These results suggest that it is premature to abandon the use of this new anaesthetic agent in ECT without controlled prospective outcome studies.
Adult↗
Adrenergic regulation of [3H]ketanserin binding sites during immobilization stress in the rat frontal cortex.
Acute immobilization stress increased serotonin and 5-hydroxyindoleacetic acid levels, the 5-hydroxyindoleacetic/serotonin ratio, and the number of [3H]ketanserin binding sites, representing serotonin-2 type receptors, in the rat frontal cortex. Peripheral administration of propranolol or central administration of 6-hydroxydopamine abolished the stress induced elevation of [3H]ketanserin binding sites. Treatment with 6-hydroxydopamine did not affect the increase in serotonin and 5-hydroxyindoleacetic acid levels, and enhanced the increase in the 5-hydroxyindoleacetic acid/serotonin ratio produced by stress. Conversely, chemical serotoninergic denervation with 5,7-dihydroxytryptamine had no influence on the stress-induced elevation of [3H]ketanserin binding sites, but abolished the serotonin and 5-hydroxyindoleacetic acid increase produced by stress. These results suggest that an intact serotoninergic system is not essential for serotonin-2 type receptor regulation during stress. Instead, the noradrenergic system, most probably through stimulation of beta-adrenoreceptors, may control the regulation of [3H]ketanserin binding sites in the rat frontal cortex during acute stress.
Animals↗
Effect of the anesthetic agent propofol on hormonal responses to ECT.
Propofol is a new anesthetic induction agent that reduces electroconvulsive therapy (ECT) seizure duration. To indirectly investigate the effect of propofol on ECT-induced acute central neurotransmitter changes, we studied neuroendocrine responses in 25 primary depressed subjects treated with ECT under either propofol or thiopentone anesthesia. Blood samples were taken prior to ECT, and then at regular intervals for 2 hr. Only the prolactin response correlated significantly with seizure duration (r = 0.52, p less than 0.01). Subjects given propofol had significantly reduced adrenocorticotropin (ACTH) (p less than 0.01) and cortisol (p less than 0.05) responses compared to thiopentone, which were independent of seizure duration. There was a trend towards a reduction in the prolactin response with propofol compared to thiopentone, but this was dependent upon the diminished seizure duration. The results indicate that propofol affects endocrine responses to ECT by two distinct mechanisms: decreasing prolactin by reducing the seizure duration and decreasing ACTH and cortisol by another process, possibly via a reduction in central noradrenergic activation.
Adrenocorticotropic Hormone↗
Increased beta 2-adrenoceptor number in peripheral sympathetic ganglia of spontaneously hypertensive rats.
We determined beta-adrenoceptor concentrations in sympathetic ganglia from adult Spontaneously Hypertensive Rats (SHR) and Wistar-Kyoto (WKY) control rats by quantitative autoradiography. Adjacent tissue sections were incubated with [125I]iodocyanopindolol, with or without excess of unlabeled (-)-propranolol, the beta 1-antagonist CGP 20712A or the beta 2-antagonist ICI 118,551. Most beta-adrenoceptors were of the beta 2-type. Their concentration was higher in the superior cervical and stellate ganglia of SHR when compared to normotensive WKY. Our results indicate that beta 2-adrenoceptor stimulation may be enhanced in sympathetic ganglia of SHR, and could play a role in the maintenance of their increased sympathetic activity.
Animals↗
Enhanced phosphoinositide hydrolysis in the pineal gland of spontaneously hypertensive rats.
We studied the phosphoinositide (PI) turnover in the pineal gland of spontaneously hypertensive rats (SHR) and compared it to that in Wistar-Kyoto and Wistar rats. Both basal and norepinephrine-stimulated PI turnover were significantly higher in the SHR than in the other strains. Prazosin (1 mumol/L) completely blocked the norepinephrine-induced PI hydrolysis in all groups. However, prazosin failed to lower the enhanced basal PI turnover in SHR. Pineal response to the cholinergic agonist carbachol was similar in all groups. These results suggest enhanced membrane phospholipid turnover in the pineal gland of SHR. Moreover, signaling via the alpha 1-adrenoceptor might be sensitized in the SHR.
Animals↗
Determination of guanine nucleotide sensitivity of [125-I]-neuropeptide Y binding in the rat pituitary gland by quantitative autoradiography.
[125I]-neuropeptide Y receptors were characterized in the rat pituitary gland using quantitative autoradiography. Scatchard analysis of saturation isotherms showed high affinity (Kd 8.5 x 10(-11) M) and single class of binding sites (Bmax 0.22 pmol/mg of protein) in the posterior lobe of the pituitary gland, with no specific binding in the intermediate or anterior lobe. Increasing concentrations of guanine nucleotide analogues and peptide YY inhibited neuropeptide Y binding. In addition, neuropeptide Y binding was pertussis-toxin-sensitive. These results add additional information about a possible neuronal (through neuropeptide Y) and hormonal (through peptide YY) regulation of posterior pituitary function, which is most probably GTP-dependent.
Animals↗
The stress induced increase of liver phosphorylase A and cyclic AMP in adrenomedullectomized and adrenalectomized rats.
In adult male rats injected with Pentobarbital, 50 mg.kg-1 i.p. and subjected immediately after administration of the anaesthetic to 400 revolutions (lasting of 6 min and 40 s) in rotating Noble-Collip drums the activity of the active form of hepatic phosphorylase was increased at time 0 after injury without respect to previous adrenomedullectomy or adrenalectomy (7 weeks or 10 days before, respectively). Completeness of surgery was checked by plasma catecholamines which were essentially near zero. The level of liver cAMP was increased in intact and adrenomedullectomized animals at time zero. 90 min after injury a recovery of enzyme activity towards basal levels was observed in contrast to cAMP which was increased in all the three groups. A net glycogenolytic response was found in the injured animals irrespective of previous surgery. It is concluded that for the stress induced activation of hepatic phosphorylase the presence of adrenal cortical and medullary tissue is not always indispensable.
Adrenal Medulla↗
[Catecholamine determination in plasma of men and rats and under stress by means of radioisotope enzymatic method (author's transl)].
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Animals↗
Inhibition of thyroid monoamineoxidase by thyroxine and some specific inhibitors.
Rat thyroid monoamine oxidase (MAO) was inhibited by the non-hydrazine derivatives paragyline and tranylcypromine to a higher degree than the hydrazine derivative iproniazide. MAO was also inhibited by monoiodotyrosine and thyroxine. These results indicate that MAO may be an important enzyme in the metabolism of biogenic amines, iodotyrosines and tyronines in the thyroid gland.
Animals↗
Changes of adrenal catecholamines and their synthesizing enzymes during ontogenesis and aging in rats.
Male Wistar specific-pathogen-free rats aged 2, 7, 17, 30, 60, 120, 200, 360 and 600 days, all killed in experiment on the same day, were examined. The body weight significantly increased until the 200th day, the weight of adrenals until the 120th day and the adrenal protein content until the 30th day of life. The adrenaline content of the adrenals increased continuously during the 600 days studied. Adrenal noradrenaline content increased rapidly over the first 17 days, remained at a stable level until the 120th day, and rose to a higher level after 200 days. The activity of adrenal catecholamine-synthesizing enzymes also increased with age: tyrosine hydroxylase gradually increased until the 360th day, dopamine-beta-hydroxylase and phenylethanolamine-N-methyl transferase until the 200th day. Our results demonstrate that, in the rat, during development there is a gradual increase of adrenal weight, adrenaline content, tyrosine hydroxylase and phenylethanolamine-N-methyl transferase activity until maturation (120th day), whereas the adrenal noradrenaline content reaches the adult values earlier, around the 17th day. During aging, adrenal catecholamines significantly increase when compared to young-adult rats (120-day-old), probably due to the elevated activity of the adrenal catecholamine-synthesizing enzymes. The increased adrenal catecholamine levels in old animals might be connected with a higher incidence of cardiovascular diseases in aged.
Adrenal Glands↗
Effect of handling and forced immobilization on rat plasma levels of epinephrine, norepinephrine, and dopamine-beta-hydroxylase.
Forced immobilization of rats triggers activation of adrenal-medullary discharge of epinephrine (EPI) and sympathetic neuronal release of norepinephrine (NE). Plasma levels of EPI reach peak values, which are about 40-fold greater than in undisturbed rats, at about 20 min and then decline to about one-third the peak levels. Plasma levels of NE are increased about 6-fold throughout the immobilization interval. Decapitation produces an 80-fold increase in plasma levels of EPI and an 8-fold increase in NE. These striking decapitation-induced increases are potentiated about 3-fold by immobilization, presumably as a consequence of an immobilization-induced alteration in the "set" of responsivity of spinal cord mechanisms controlling sympathoadrenal medullary discharge. Even minor disturbances produce highly significant increases in plasma EPI and NE and special precautions must be observed when studies involving plasma catecholamines or their effects are performed in animals.
Animals↗
[Dynamics of serotonin level changes in the hypothalamus, septum, and amygdala in rats under stress (author's transl)].
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Amygdala↗
Posterior pituitary dopamine and noradrenaline content: effect of thirst, ethanol and saline load.
Dopamine and noradrenaline content in the posterior pituitary were found to be lower in alcohol-loaded unanesthetized rats than in rats thirsting for 72 h. Dopamine content was also found to be lower in anesthetized saline loaded rats in comparison with hydropenic animals. It is concluded that in situations in which an increase of vasopressin release is expected, the posterior pituitary content of catecholamines will also be increased, and vice versa, which might imply their role in the release of vasopressin.
Animals↗
Catecholamines in individual hypothalamic nuclei of acutely and repeatedly stressed rats.
Norepinephrine (NE) and dopamine (DA) concentrations in 17 individual hypothalamic nuclei and 3 other brain regions were measured in rats, acutely or repeatedly stressed by immobilization, using a microdissection technique and a radioisotopic-enzymatic assay. Following the first 20 min immobilization (IMO) a significant NE decrease in the ventromedial (NVM) and supraoptic (NSO) nuclei and a DA decrease in the arcuate nucleus (NA) as well as NE and DA increase in the dorsomedial nucleus (NDM) were seen. Repeated IMO (40 times) produced a NE increase in the NVM, NDM, NSO paraventricular nucleus (NPV) and median eminence (ME), and a DA increase in the NDM and NPV. Changes of NE and DA concentration found in some individual hypothalamic nuclei under the influence of stress indicate that catecholamines (CAs), particularly in the medial basal hypothalamus, could be involved in the regulation of some neuroendocrine processes which are being activated during stress, especially ACTH release.
Animals↗
Dopamine-beta-hydroxylase, noradrenaline and granular vesicles in the autonomic postganglionic nerve.
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Animals↗