Search PubMed⌕ Search

Biomedical subjects

C Castellano

Publications and source records attributed to C Castellano.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effect of ethanol on memory consolidation in mice: antagonism by the imidazobenzodiazepine Ro 15-4513 and decrement by familiarization with the environment.

Three sets of experiments were carried out with CD1 mice tested in a one-trial inhibitory avoidance task. In a first set of experiments the posttraining administration of ethanol (1 or 2 g/kg) impaired, while that of the imidazobenzodiazepine Ro 15-4513 (5 or 10, but not 2.5 mg/kg) improved the retention performance of the animals. In a second set of experiments a by itself ineffective dose of Ro 15-4513 (2.5 mg/kg) antagonized the effect of ethanol (1 and 2 kg/kg). These results are discussed on the basis of the interaction of these drugs with the GABAergic system. In a third set of experiments, in which the performances of mice familiarized with the apparatus were compared with those of non-familiarized mice, ethanol was less effective in impairing memory processes of the experienced subjects. These results are discussed in terms of attenuation of emotionality, resulting in impaired retention, following posttraining ethanol administration.

Animals↗
PubMed1990

Effect of chronic GM1 ganglioside administration on passive avoidance retention in mice.

Chronic administration of GM1 ganglioside to C57BL/6 mice during development improved passive avoidance retention. A significant weight increase was also evident in the treated animals in comparison with the control group. The results are discussed in terms of the possible effects exerted by GM1 upon the cholinergic mechanisms of this inbred strain.

Animals↗
PubMed1990

Different levels of acetylcholinesterase and choline acetyltransferase activities in C57Bl/6 and DBA/2 mice are not accompanied with different density of cortical acetylcholinesterase reactive fibers.

Mice of the inbred strains C57B1/6 and DBA/2 show strain-dependent behavioural differences which have been correlated with variations in the organization of brain cholinergic systems. The aim of our study was to analyse the extent of cholinergic interstrain differences in circumscript brain regions of C57B1/6 and DBA/2 mice. The biochemical determination of choline acetyltransferase and acetylcholinesterase in cortical areas, basal forebrain and striatum showed significantly lower enzyme activities in most of the regions of C57B1/6 mice. The deficit was most pronounced in the basal forebrain/diagonal band, in the piriform cortex, and striatum. The density of acetylcholinesterase-stained cortical fibres did not reflect the biochemical interstrain differences. This may be due to a different enzyme content in the nerve fibers of the two mice strains. The previous findings are discussed in terms of brain cholinergic disorders in which the extent of damage but also the proportions of regional deficits may influence the pattern of behavioural dysfunctions.

Acetylcholinesterase↗
PubMed1990

Oxiracetam prevents mecamylamine-induced impairment of active, but not passive, avoidance learning in mice.

The nicotinic antagonist mecamylamine (2.5 and 5 mg/kg/IP) depressed both active (shuttle-box) and passive (step-through) avoidance learning in mice of the DBA/2 strain. The nootropic drug oxiracetam (50 and 100 mg/kg/IP) improved acquisition in the multitrial active avoidance test, but had no effect on one-trial passive avoidance learning. When the two drugs were combined, oxiracetam did not counteract mecamylamine-induced impairment of passive avoidance learning, even if it maintained a facilitating action on shuttle-box avoidance acquisition in mice receiving the nicotinic receptor blocker. Prevention of mecamylamine-induced shuttle-box avoidance depression by oxiracetam indicates that central nicotinic mechanisms are probably involved in the improving effects exerted by nootropic drugs on learning.

Animals↗
PubMed1990

Effects of post-training bicuculline and muscimol on retention: lack of state dependency.

Immediate post-training intraperitoneal injections of the GABA antagonist bicuculline (0.25 or 0.5 mg/kg) or of the GABA agonist muscimol (1.0 or 2.0 mg/kg) improved and impaired, respectively, retention of CD1 mice tested 24 h after training in a one-trial inhibitory avoidance task. Administration of bicuculline or muscimol prior to the retention test did not modify retention latencies of mice that had received either saline or the same drug immediately after training. These findings indicate that the effects of post-training administration of bicuculline and muscimol on retention are not state dependent and, thus, argue against a general state-dependency interpretation of the effects of post-training treatments affecting retention. The findings are consistent with previous evidence indicating that GABAergic drugs affect retention through influences on memory storage processes.

Animals↗
PubMed1990

Involvement of the amygdaloid complex in neuromodulatory influences on memory storage.

Neuromodulatory systems activated by training experiences appear to play a role in influencing memory storage processes. The research summarized in this paper examined the effects, on memory, of posttraining administration of treatments affecting adrenergic, opioid peptidergic and GABAergic systems. When administered after training, drugs affecting these systems all produce dose- and time-dependent effects on memory storage. The drug effects on memory are blocked by lesions of the amygdaloid complex as well as lesions of the stria terminalis, a major amygdala pathway. The effects of drugs affecting these neuromodulatory systems are also blocked by injections of beta-adrenergic antagonists administered to the amygdaloid complex. Thus, the findings suggest that the neuromodulatory systems affect memory storage through influences involving the activation of beta-adrenergic receptors within the amygdala. These findings are consistent with the view that the amygdala is involved in regulating the storage of memory in other brain regions.

Amygdala↗
PubMed1990

Picrotoxin enhances latent extinction of conditioned fear.

Male CD1 mice received 20 pairings of tone and footshock (FS) or tone alone in an arm of a Y-maze on Day 1. On Day 2 either extinction (tone alone) or no extinction was followed immediately by saline or picrotoxin (0.5 or 1.0 mg/kg ip). Nonextinguished groups received only saline or picrotoxin (1.0 mg/kg ip) on Day 2. Other groups received saline or picrotoxin (1.0 mg/kg) 2 hr after extinction. On Day 3 all mice were placed in the Y-maze (with doors to all 3 alleys open), and total alley entries during a 2-min test session were recorded. Day 1 FS training resulted in reduced alley entries during the test session. Day 2 extinction session significantly attenuated the effects of the FS training. Day 3 performance of mice given picrotoxin (1.0 but not 0.5 mg/kg) immediately postextinction was comparable to that of mice not given FS on Day 1. The findings suggest that picrotoxin enhanced extinction of conditioned fear.

Animals↗
PubMed1989

Blocking of morphine-induced locomotor hyperactivity by amygdaloid lesions in C57BL/6 mice.

Bilateral lesions of the amygdaloid complex in C57BL/6 mice prevented the occurrence of morphine-induced hypermotility (running fit). This effect, that was different from that observed after hippocampal lesions but similar to that observed after caudate lesions, confirms the role of the basal ganglia catecholaminergic system in the development of the motor stimulation consecutive to the administration of this opiate receptor agonist.

Amygdala↗
PubMed1989

Synthesis and some properties of a homologous series of beta-carboline-3-carboxylic esters.

A homologous series of esters of beta-carboline-3-carboxylic acid was prepared by a new synthetic procedure. The first members of the series are convulsant or pro-convulsant agents while those with acyl residues longer than C4 show anticonvulsant activity. The affinity of the members of the series for the benzodiazepine receptor from rat brain decreases with the increasing chain length of the esters. The pentyl ester was studied in particular for its anti-convulsant effect on rats and mice treated with cardiazol. The compound also acts as a membrane stabilizer by inhibiting red cell hypotonic hemolysis and rat brain Na/K ATPase; its LD50 value is 12.5 mg/Kg and of particular interest is its lack of inhibitory effect on memory retention in mice at doses at which diazepam has inhibitory effects.

Animals↗
PubMed1989

Effects of naloxone and naltrexone on memory consolidation in CD1 mice: involvement of GABAergic mechanisms.

The involvement of GABAergic mechanisms in the effects exerted by the opioid antagonists naloxone and naltrexone on memory consolidation was investigated in CD1 mice tested in a one-trial inhibitory avoidance task. In a first group of experiments posttraining administration of naloxone (2.0 and 4.0 but not 1.0 mg/kg) and naltrexone (0.5 and 1.0 but not 0.25 mg/kg), as well as those of the GABA-antagonists picrotoxin (0.5 and 1.0 but not 0.25 mg/kg) and bicuculline (0.25 and 0.5 but not 0.1 mg/kg) enhanced, whereas those of the GABA-agonist muscimol (1.0 and 2.0 but not 0.5 mg/kg) impaired retention on a 24-hr test. In a second group of experiments, picrotoxin, or bicuculline, administration enhanced, while muscimol treatment attenuated the effects of naloxone and naltrexone on retention. The results suggest that naloxone and naltrexone may influence memory consolidation in CD1 mice by interacting with the GABAergic system.

Animals↗
PubMed1989

Behavioral effects of morphine in mice: role of experimental housing.

Behavioral effects of morphine were assessed in isolated-timid Swiss mice, and were compared with those observed following morphine administration in nonaggressive-grouped subjects. For this purpose saline- and morphine- (0.5, 1.0, 2.5, and 5.0 mg/kg, IP) injected isolated-timid and nonaggressive-grouped mice interacting with a social partner were observed during a 4-min test. Three main points emerged from the results: a) in basal conditions, compared with social mice, in timid mice the offensive ambivalent behaviors were significantly less pronounced, while the defensive ambivalent behaviors (and all flight behaviors) were significantly more evident; b) 2.5 mg/kg of morphine increased offensive and decreased defensive ambivalent behaviors in timid mice; c) in social mice morphine (2.5 mg/kg) treatment increased defensive ambivalent behaviors and time spent in crouch. The results, which show that the behavioral effects of morphine depend on the state of the individual, are interpreted on the basis of the antiemotional properties of this opiate.

Aggression↗
PubMed1989

Post-training systemic and intra-amygdala administration of the GABA-B agonist baclofen impairs retention.

The effects of the GABA-B receptor agonist baclofen on memory storage were studied in two series of experiments. In the first series, CD-1 mice were trained in two aversively motivated tasks: a one-trial inhibitory avoidance task and a classical conditioning task (conditional emotional response). Immediate post-training ip administration of (+/-)baclofen (10 and 30 mg/kg) impaired retention of animals in both tasks. The effect was time-dependent: Retention was not affected by baclofen administered 120 min after training. In the second series of experiments, which used Sprague-Dawley rats, post-training intra-amygdala administration of baclofen impaired retention of an inhibitory avoidance response. These results support the view that the GABAergic system is involved in the modulation of memory storage and that the amygdaloid complex may be a critical site for effects of drugs affecting the GABAergic system.

Amygdala↗
PubMed1989

Retention enhancement with post-training picrotoxin: lack of state dependency.

Immediate post-training intraperitoneal administration of the GABA-antagonist picrotoxin (0.5 or 1.0 mg/kg) significantly enhanced retention of CD1 mice tested 24 h after training in an inhibitory avoidance task. Administration of picrotoxin prior to the retention test did not affect the retention performance of mice given post-training injections of either saline or picrotoxin. These findings indicate that the memory-enhancing effects of post-training administration of picrotoxin are not state-dependent.

Animals↗
PubMed1989

Lens rotation and spherocylindrical over-refraction as predictors for soft toric lens evaluation.

Prospective data from 72 patients (128 eyes) fitted with one type of soft toric lens of the double slab-off design were analyzed for lens rotation and spherocylindrical over-refraction (SCO) for the purpose of assessing their accuracy as predictors in soft toric evaluation. Initial trial lens data were compared with final lenses and best spectacle refraction. The mean difference in lens rotation between the initial and final lens visits was 9.9 degrees (SD = 11.5 degrees), and the mean difference between the actual refractive astigmatism and the expected astigmatism, calculated from ophthalmic cross-cylinder equations, was 0.22 D (SD = 0.12 D). Considerable variability existed in lens rotation in the various ametropias during the course of several assessments; SCO provides the best evidence of the fit of toric soft lenses. The implications for other lens types are discussed.

Astigmatism↗
PubMed1989

Age-determined changes in the effects of a newly synthetized cholinesterase inhibitor on exploratory behavior, memory and striatal cholinesterase activity in rats.

The newly synthetized cholinesterase inhibitor C-8 (a structural analogue of physostigmine) at a dose of 4 mg.kg-1 exerted no inhibitory effect on the spontaneous locomotor activity in 2-, 10- and 22-month old male Wistar rats. Upon open field test, C-8 facilitated the process of habituation in the rats of all three groups. In a passive avoidance situation (step-down and step-through) C-8 had a favorable effect on the memory of 22-month old rats mainly. C-8 inhibited the cholinesterase activity in the striatum of 2-month old rats by 29%, in 10-month old rats by 73%, and in 22-month old rats by 30%.

Aging↗
PubMed1988

Prenatal antagonism of stress by naltrexone administration: early and long-lasting effects on emotional behaviors in mice.

The effects of prenatal exposure to stress and to naltrexone on emotional behaviors were studied in CD1 mice during ontogeny and in the adulthood. During ontogeny (a) lower body weights were initially found in pups born by mothers injected with naltrexone; (b) treatments did not affect sensory motor development except in the case of the cliff aversion reflex which occurred earlier in pups prenatally exposed to stress; (c) measures of ultrasonic vocalizations in stressful context showed that the amount of vocalizations emitted by pups born by stressed mothers was significantly higher than that emitted by pups born by naltrexone injected and control mothers (d) an examination of mother-offspring interactions on the very first day of observation indicated a consistent trend in stressed mothers to be more responsive to their pups. In adulthood, ultrasonic calls in courtship after short and long periods of isolation showed a time-dependent decrease of vocalizations in males prenatally exposed to naltrexone. These results indicate that the modifications of emotionality evident during early development are directly related to the reactivity of the mothers to the experimental treatments.

Animals↗