Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002622 (amnesia)
 5,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vasopressin and oxytocin exert pronounced effects on behaviour by a direct action on the brain. A single injection of vasopressin results in a long-term inhibition of extinction of a conditioned avoidance response suggesting that vasopressin triggers a long-term effect on the maintenance of a learned response, probably by facilitation of memory processes. In addition vasopressin improves passive avoidance behaviour, delays extinction of appetitive discrimination tasks, affects approach behaviour to an imprinting stimulus in ducklings, improves copulation rewarded behaviour of male rats in a T-maze, prevents or reverses amnesia induced by electroconvulsive shock, CO2 inhalation, pentylenetetrazol or puromycin. The majority of these effects of vasopressin in the various and sometimes relatively complex tasks may be explained by stimulatory influences of this neuropeptide on memory processes. Generally oxytocin exerts effects which are opposite to those of vasopressin and it has been suggested that oxytocin may be an amnesic neuropeptide. Various limbic system structures seem to act as the anatomical substrate for the behavioural effects of vasopressin. In particular the amygdala, the dentate gyrus of the hippocampal complex, the ventral hippocampus and the dorsal septum seem to be involved. Evidence has been obtained from experiments with homozygous diabetes insipidus rats and from experiments in which antisera were applied that endogenous vasopressin and oxytocin play a physiological role in brain processes related to memory. It appears that highly active fragments can be generated from vasopressin and experiments in which a fragment of vasopressin ([pGlu4, Cyt6]AVP-(4-8)) as well as an AVP-antagonist were used, reveal that the vasopressin receptors mediating the behavioural effects are situated in the brain and differ in specificity from the peripheral (blood pressure) vasopressin receptors. Generally the clinical data obtained so far with vasopressin treatment are in agreement with the results from animal experiments and they support the notion on the involvement of vasopressin in memory function. The sometimes reported conflicting results on vasopressin effects in certain patients (Korsakoff or Alzheimer) may have to do with the wide-spread pathology in these diseases.
 ...
PMID:Vasopressin and oxytocin. Their presence in the central nervous system and their functional significance in brain processes related to behaviour and memory. 346 10

Vasopressin and oxytocin exert pronounced effects on behavior by a direct action on the brain. A single injection of vasopressin results in a long-term inhibition of extinction of a conditioned avoidance response suggesting that vasopressin triggers a long-term effect on the maintenance of a learned response, probably by facilitation of memory processes. In addition vasopressin improves passive avoidance behavior, facilitates retention of sexually motivated T-maze choice behavior in male rats, delays extinction of an appetitive discrimination task, affects approach behavior to an imprinting stimulus in ducklings, delays the postcastration decline in copulatory behavior in male rats, prevents or reverses amnesia induced by electroconvulsive shock, CO2 inhalation, pentylenetetrazol or puromycin. The majority of these effects may be explained by stimulatory influences of vasopressin on memory processes. Generally oxytocin exerts effects which are opposite to those of vasopressin and it has been suggested that oxytocin may be an amnesic neuropeptide. Evidence has been obtained that endogenous vasopressin and oxytocin play a physiological role in brain processes related to memory. Various limbic system structures seem to act as the anatomical substrate for the behavioral effects of vasopressin and different neurotransmitter systems seem to be involved. It is postulated that in case vasopressin affects retrieval processes the site of action is located in the amygdala and the dentate gyrus of the hippocampal complex with dopamine and serotonin as the respective neurotransmitter systems involved.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Hypothalamic neuropeptides and memory. 399 53

Alterations in memory storage processes that occur in senescence were investigated by challenging young and old female "small Wistar" rats with posttraining administration of CO2, amphetamine or morphine, and measuring retention performance. Neither duration of CO2 immersion, nor the time of CO2 immersion after training had a differential amnestic effect with age on retention of a one-trial, shock-motivated inhibitory avoidance task. These results indicate that the times during which memory is susceptible to disruption for old and young rats are similar. Challenge with drugs, however, did reveal age-related alterations in memory storage processes. Amphetamine attenuated CO2-induced amnesia in young rats, but had no effect in old rats. This could not be attributed to a general decline in response to amphetamine in old rats because amphetamine increased open field activity of both young and old animals. Morphine also had a differential effect on memory with age: it caused amnesia in old rats trained in a one-trial hot plate escape task, while having no effect on retention performance of young rats. Thus, the modulatory influence of catecholamine and opioid systems on memory processes is probably altered in senescence.
 ...
PMID:Memory consolidation in senescence: effects of CO2, amphetamine and morphine. 681 51

N-(2-Dimethylaminoethyl)carboxamide (1a-d), 2-dimethylaminoethyl alkyl ether (2a, b), and 2-dimethylaminoethyl 2-hydroxy-2-phenethyl ether (3a-c) and its amino and methylene analogues (3d, 4) have been screened for antiamnestic and antihypoxic activities in mice. A clear reversing effect on electroconvulsive shock-induced amnesia was found with 1a-d, 2a,b, and 2-dimethylaminoethyl 2-hydroxy-2-phenylethyl ether (3a). However, a protective effect against hypoxia was only observed with 3a. Compound 3a, which displayed the dual activity, was further investigated for ameliorating effect on CO2-induced memory impairment, and it was found to be more potent than indeloxazine and bifemelane. In addition, the acute toxicity of 3a in mice was significantly lower than that of tacrine, but its serum-to-brain penetration ability in rats was less than that of the reference drugs.
 ...
PMID:Studies on cognitive enhancing agents. I. Antiamnestic and antihypoxic activities of 2-dimethylaminoethyl ethers and related compounds. 758 70

A series of 2-(2-aminoethoxy)-1-phenylethanols having a variety of N- and phenyl-substitution patterns as well as 5- and 6-membered heteroaryl counterparts of our prototype compound 1 (2-(2-dimethylaminoethoxy)-1-phenylethanol) have been prepared and evaluated for antiamnestic and antihypoxic activities. Compound 3b, the 3-methylphenyl analogue of 1, proved to be significantly more potent than 1 in reversing electroconvulsive shock-induced amnesia as well as CO2-induced learning-impairment in mice. It exhibited low acute toxicity in mice and afforded a greater brain/serum concentration ratio than 1 after oral administration to rats.
 ...
PMID:Studies on cognitive enhancing agents. II. Antiamnestic and antihypoxic activities of 1-aryl-2-(2-aminoethoxy)ethanols. 758 71

2-(2-Aminoethoxy)-1-hydroxyethyl derivatives of bicyclic arenes (naphthalene, thianaphthene, benzofuran, and indole) were prepared and screened for antiamnestic (AA) and antihypoxic (AH) activities which were evaluated by measuring the reversing potency in electroconvulsion-induced amnesia and the protective effect against hypoxia, respectively, in mice. Compound 3o, 1-(benzo[b]thiophen-5-yl)-2- (2-diethylaminoethoxy)ethanol, showed the best AA and AH activity profile, being superior to our prototype compound, 2-(2-dimethylaminoethoxy)-1-phenylethanol (1). Elongation of the ethylene linkage in the side chain of 3o to 3- and 4-carbon moieties brought about a significant decrease in AH activity. Compound 3o was further investigated for its protective effect against CO2-induced memory impairment and for acute toxicity in mice. It is ten-fold more potent than tacrine in the amnesia-reversal assay and is considerably less toxic than tacrine.
 ...
PMID:Studies on cognitive enhancing agents. III. Antiamnestic and antihypoxic activities of a series of 1-bicycloaryl-2-(omega-aminoalkoxy)ethanols. 758 72

Effects of MCI-225, [4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-d]pyrimidine monohydrate hydrochloride] on experimental amnesia were studied in rats and compared with those of THA [9-amino-1,2,3,4-tetrahydroacridine]. In the Morris-type water maze task, MCI-225 (1-10 mg/kg, PO) reduced the spatial learning impairment induced by scopolamine (0.5 mg/kg, IP). In a passive avoidance (PA) task, administration of MCI-225 prior to training (1-30 mg/kg, PO) lessened the carbon dioxide (CO2)-induced amnesia in a dose-dependent manner. MCI-225 (1-100 mg/kg) did not affect gross behavior. THA (0.1-3 mg/kg, PO) reduced scopolamine-induced learning deficits in the water maze task, but the effect was not significant. THA (0.3-3 mg/kg, PO) also ameliorated the CO2-induced amnesia, although slightly, in the PA task. THA (10 mg/kg, PO) increased locomotor activity and higher dose of THA (30 mg/kg, PO) induced tremor, hypersalivation, and muscle relaxation. These results suggest that MCI-225 lessens impairments in learning and memory without causing serious behavioral abnormalities.
 ...
PMID:Effects of a novel compound MCI-225 on impaired learning and memory in rats. 809 Aug

Electrophysiological studies are often distressing for patients. We devised a regime of continuous infusion of midazolam and fentanyl during electrophysiological studies without the presence of a specialist anaesthetist. The effects on key hemodynamic and respiratory variables and level of sedation were evaluated in detail in the first 775 patients. The safety of this practice was evaluated in 1,344 consecutive patients. Doses were calculated according to patients' weight and age. A mean total dose of 26 mg of midazolam and 115 mcg of fentanyl were infused. Satisfactory sedation was achieved in 97% of patients. The mean duration of procedure was 188 +/- 90 minutes. Complete amnesia of the procedure was obtained in 87% of patients. Sedation caused clinically insignificant changes in respiratory rate, oxygen saturation, end-tidal CO2 and blood pressure. There were no major complications related to sedation. Upper airway obstruction, usually minor, occurred in 42% and some restlessness in 20% of sedated patients. The assistance of a specialist anesthetist was required in 0.3% of sedated patients for management of restlessness, hypoventilation, or obstructive sleep apnea. The amount of distress experienced by sedated patients (n = 775) was significantly less compared to a previous series of nonsedated patients (n = 775) undergoing electrophysiological studies (P < 0.001). The degree of distress experienced by patients during electrophysiological studies can be reduced significantly by sedation with intravenous midazolam and fentanyl. Continuous infusion is an efficient, safe, and effective way of administering midazolam and fentanyl.
 ...
PMID:Efficacy and safety of a new protocol for continuous infusion of midazolam and fentanyl and its effects on patient distress during electrophysiological studies. 939 7

We examined memory improvement with respect to the effects of gastrin-releasing peptide (GRP) in male C57BL/6J mice under conditions of experimentally induced amnesia. GRP was administered following training in a one-trial passive avoidance test. In Experiment 1, the drug scopolamine (1 or 2 mg/kg, ip) was used to induce amnesia prior to training, and GRP (32 nmol/kg, ip) or saline (control) was administered immediately after training. Results indicate that GRP at this dose improved memory only when the dosage of scopolamine was relatively low (1 mg/kg). In Experiment 2, CO2-induced amnesia was employed. Mice were placed in a chamber filled with CO2 or air (control) immediately after acquisition training. Subsequently, they were administered either saline or GRP (32 nmol/kg, ip). Significantly longer light-dark latency was observed in all mice that received GRP (both experimental and control groups). In total, our results indicate that the effect of GRP at this dose on the improvement of impaired memory is dependent on the degree of impairment. Furthermore, because CO2-induced hypoxia is known to decrease acetylcholine release in the brain, our results also suggest that GRP and its receptor may interact with the cholinergic system in the central nervous system.
 ...
PMID:Posttraining administration of gastrin-releasing peptide improves memory loss in scopolamine- and hypoxia-induced amnesic mice. 1156 62

The main end points for sedation during endoscopy are patients' satisfaction, short duration of the procedure, and safety. During the last year, attention has focused on attempting to identify the "ideal" candidate for moderate sedation/analgesia and on the importance of providing the patient with appropriate information before the procedure. The increasing pressure to perform more procedures, reduce costs, and achieve shorter patient turnaround times has affected recent approaches to sedation during endoscopy, focusing attention on alternatives to pharmacological sedation such as providing relaxing music, using small-caliber endoscopes for unsedated peroral gastroscopy, and using magnetic endoscopic imaging to increase tolerance and reduce discomfort during colonoscopy. The results, however, have not been convincing. The role of benzodiazepines was discussed in some studies, highlighting the well-known effect of midazolam on postprocedural amnesia, its pharmacological profile and tolerability after intranasal spraying in healthy volunteers, and the efficacy and safety of this route of administration as an alternative to intravenous administration in diagnostic upper gastrointestinal endoscopy. The form of sedation for gastrointestinal endoscopy that has attracted great interest over the last year is the use of intravenous propofol, either alone or with concomitant benzodiazepines or opioids. As expected in view of the drug's known pharmacological properties, the quality of sedation was better and recovery time was shorter in patients treated with propofol. However, important questions involving the narrow therapeutic range and the mode of administration of propofol (by endoscopists or nurses, or by anesthesiologists) remain open. One important aspect of sedation procedures is prevention of cardiopulmonary complications. The use of electronic monitoring techniques, with a pulse oximeter, has been recommended as a standard procedure during digestive endoscopy; however, pulse oximetry no longer reflects the normal ventilatory functions and does not detect episodes of severe CO2 retention. CO2 monitoring by transcutaneous measurement - or better, by capnography - appears to be useful, as an alternative to pulse oximetry, as a measure of hypoventilation, and for detecting potentially important abnormalities in respiratory activity in patients undergoing sedation for gastrointestinal endoscopy. With regard to preparation for endoscopic procedures, several "ideal" formulas for bowel preparation have been presented. These include the use of sodium phosphate compounds as an alternative to polyethylene glycol electrolyte lavage solutions (PEG-ELS); however, the results so far have been conflicting. The best and most cost-effective bowel cleansing procedure for colonoscopy and sigmoidoscopy has yet to be established.
 ...
PMID:Preparation, premedication and surveillance. 1256 Oct 3


<< Previous 1 2