Drugs online research references
Neurobiol Learn Mem. 1998 May;69(3):241-57.
The effects of muscarinic cholinergic receptor blockade in the rat anterior cingulate and Prelimbic/Infralimbic cortices on spatial working memory.
Ragozzino ME, Kesner RP.
Department of Psychology, University of Utah, Salt Lake City, Utah, 84112, USA.
Previous findings indicate that cholinergic input to the medial prefrontal cortex may modulate mnemonic processes. The present experiment determined whether blockade of muscarinic cholinergic receptors in the rodent anterior cingulate and prelimbic/infralimbic cortices impairs spatial working memory. In a 12-arm radial maze, a working memory for spatial locations task was employed using a continuous recognition go/no-go procedure. Rats were allowed to enter 12 arms for a reinforcement. Of the 12 arm presentations, 3 or 4 arms were presented for a second time in a session that did not contain a reinforcement. The number of trials between the first and second presentations of an arm ranged from 0 to 6 (lags). Infusions of scopolamine (1, 5, and 10 microgram), a muscarinic cholinergic antagonist, into the prelimbic/infralimbic cortices, but not the anterior cingulate cortex, significantly impaired spatial working memory in a lag- and dose-dependent manner. The deficit induced by scopolamine (10 microgram) was attenuated by concomitant intraprelimbic/infralimbic injections of oxotremorine (2 microgram) a muscarinic cholinergic agonist. A separate group of rats was tested on a successive spatial discrimination task. Injections of scopolamine (1, 5, and 10 microgram) into the prelimbic/infralimbic cortices did not impair performance on the spatial discrimination task. These findings suggest that muscarinic transmission in the prelimbic/infralimbic cortices, but not the anterior cingulate cortex, is important for spatial working memory. Copyright 1998 Academic Press.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9707488&dopt=Abstract
Regul Pept. 1998 Jun 30;74(2-3):97-103.
Attenuation of scopolamine-induced spatial learning impairments by an angiotensin IV analog.
Pederson ES, Harding JW, Wright JW.
Program in Neuroscience, Washington State University, Pullman 99164, USA.
Recently, a receptor for the angiotensin II(3-8) (Ang IV) hexapeptide, was discovered in the hippocampus, suggesting a possible role in learning. The present study utilized intracerebroventricularly (icv) infused scopolamine hydrobromide (scop) to disrupt spatial learning in the circular water maze, followed by the Ang IV analog norleucine1-Ang IV (Nle1-Ang IV), to restore normal performance. Rats were icv pretreated with either scop or artificial cerebrospinal fluid (aCSF) followed by either icv injected Nle1-Ang IV or aCSF, and then behaviourally tested. During acquisition training, each animal's latency to locate the platform, path distance, speed, and efficiency ratios were measured. A probe trial was conducted on the final day of training and the time spent in the target quadrant and the number of crossings over the former location of the platform (annulus crossings) were observed. The results indicate that those animals treated with scop followed by aCSF performed poorly during acquisition training as compared with controls. In contrast, those animals that received scop followed by Nle1-Ang IV attained equivalent latencies, distances, and efficiency ratios to find the platform as those achieved by controls. There were no observed differences in swimming speed, thus arguing against drug-induced motor impairment. During the probe trial, animals treated with scop followed by aCSF spent less time in the target quadrant and made fewer annulus crossings as compared to controls, while the scop, Nle'-Ang IV treated animals performed equivalently to controls. These results suggest that Nle1-Ang IV acts to counteract the disruption of spatial learning induced by scopolamine.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9712169&dopt=Abstract
venus.iteb.serpukhov.su
Two new behavioural tests in rats are described which demonstrate the fast consolidation of the long-term memory (LTM) in a dangerous natural situation (water escape). It is shown that after one-trial learning of the motor skill (jumping out of the water), long-term memory traces are retained without forgetting and are resistant to the blockade of M-cholinoreceptors by scopolamine (2 mg/kg) and of D1/D2 dopamine receptors by haloperidol (10 mg/kg) as well as electroconvulsive shock applied tank wall, learning of necessary motor skills, automatization and minimization of the skilled movements in 1.5-3.0 min, after 5 to 7 trials at two-second intervals (superfast learning) is demonstrated. It is suggested that the superfast consolidation of LTM (several minutes) is possible in life-threatening situations, the necessary time being 1-2 orders of magnitude less than it is generally accepted in the modern theories of memory. The proposed behavioural models may be helpful in investigation of some fundamental physiological and molecular mechanisms of stable neuronal interactions, as a basis for LTM consolidation.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9718571&dopt=Abstract
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