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J R Criado

Publications and source records attributed to J R Criado.

26 records · Page 2Linked to original sources
PubMed1994

Pharmacology of ethanol and glutamate antagonists on rodent sleep: a comparative study.

Twenty-five Sprague-Dawley rats were implanted with electrodes for standard sleep-wake cycle recordings. A guide cannula was stereotaxically implanted into the lateral ventricle. Rats were divided into five groups (n = 5) and challenged with an intraventricular administration of 10 microliters of a 5 nM solution of either: ethanol (EtOH), MK-801, AP5 (noncompetitive and competitive NMDA receptor antagonists, respectively), CNQX (AMPA receptor antagonist), or saline. Rats were recorded polygraphically for the following 4 h. Results showed that, at comparable doses, all tested drugs reduced REM sleep. No significant changes were detected in slow-wave sleep or wakefulness. This selective effect of glutamatergic antagonists suggests that glutamate may be a selective modulator of REM sleep. These findings also show that EtOH shares similar pharmacological effects on the sleep-wake cycle of the rat. Ultimately, glutamatergic mechanisms could contribute to the EtOH-mediated reduction of REM sleep.

Animals↗
PubMed1994

Transcripts encoding a neural membrane CD26 peptidase-like protein are stimulated by synaptic activity.

We isolated a cDNA clone, named BSPL, that encodes a brain-specific dipeptidyl peptidase-like protein with 30% identity and 50% similarity to CD26, a lymphocyte membrane antigen involved in T-cell activation. BSPL lacks, however, the catalytic residue responsible for peptidase activity. The expression of BSPL is widespread throughout the CNS but restricted to neurons under normal conditions. Twenty-four hours after injection of kainic acid into the hippocampus, a dramatic increase in the concentration of BSPL mRNA was detected by in situ hybridization in the CA3 region of the injected hemisphere as compared with the contralateral hemisphere or sham-injected animals. An increase in the steady-state level of BSPL mRNA concentration was also found following tetanic stimulation of the perforant path to produce LTP in granule cells of the dentate gyrus. Hybridization signals could be detected in dendritic processes of pyramidal neurons and in some glial cells upon either type of stimulation. These data suggest that BSPL may be involved in synaptic plasticity.

Amino Acid Sequence↗
PubMed1992

Tolerance to ethanol's effects on operant performance in rats: role of number and pattern of intoxicated practice opportunities.

Acquisition and retention of tolerance to ethanol's rate-decreasing effects on operant performance were examined in rats which received a 52-day regimen of ethanol or saline injections prior to and/or after each daily session. Eight groups of rats differed on: (a) number of days with intoxicated practice (pre-session ethanol); (b) intermittent (spaced) or daily (massed) intoxicated practice; and (c) post-session ethanol or saline on non-intoxicated practice days. Massed practice groups were given their presession saline days prior to their pre-session ethanol days. Ethanol dose-effect tests were given prior to, during, and after the chronic injection regimen. Under both spaced and massed practice conditions, the magnitude of tolerance developed increased directly with the number of pre-session ethanol days, even when absolute ethanol exposure was constant. No group showed complete tolerance loss. The post-session ethanol supplements (a) facilitated tolerance development in spaced practice groups and tolerance loss in massed practice groups, (b) blocked ethanol's low dose rate-increasing effects, and (c) produced an acute withdrawal-like performance disruption the next day. The results suggest that both intoxicated practice and practice during acute ethanol withdrawal influence the acquisition and retention of compensatory behaviors during ethanol tolerance development.

Alcoholic Intoxication↗
PubMed1990

Potentiation of cocaine's discriminative effects by caffeine: a time-effect analysis.

The effects of caffeine upon the discriminative and rate-altering effects of cocaine were examined in rats. Using a food-reinforced two-lever operant procedure, 12 male Sprague-Dawley rats were trained to discriminate between 10 mg/kg cocaine and saline. Time-effect analysis of the training dose resulted in a median effective time interval (the duration of the discriminable effects of cocaine in producing 50% cocaine-appropriate responding), of 60.5 minutes postinjection. Caffeine partially generalized to the cocaine stimulus and, when administered with cocaine, produced a dose- and time-dependent increase in the percentage of drug-appropriate responding. Data are discussed with reference to our previous results with cocaine-caffeine interactions.

Animals↗
PubMed1989

The discriminative stimulus properties of ethanol and acute ethanol withdrawal states in rats.

Twelve male Sprague-Dawley rats were trained in a standard two-choice Drug 1-Drug 2 discrimination task utilizing 3.0 mg/kg chlordiazepoxide (CDP, an anxiolytic drug) and 20 mg/kg pentylenetetrazol (PTZ, an anxiogenic drug) as discriminative stimuli under a VR 5-15 schedule of food reinforcement. Saline tests conducted at specific time points after acute high doses of ethanol (3.0 and 4.0 g/kg) indicated a delayed rebound effect, evidenced by a shift to PTZ-appropriate responding. Insofar as such a shift in lever selection indexes a delayed anxiety-like state, this acute 'withdrawal' reaction can be said to induce an affective state similar to that seen with chronic ethanol withdrawal states. Ethanol generalization tests: (1) resulted in a dose- and time-dependent biphasic generalization to CDP, (2) failed to block the PTZ stimulus and (3) failed to block the time- and dose-dependent elicitation of an ethanol-rebound effect. These data suggest that ethanol's anxiolytic effects are tenuous.

Affect↗
PubMed1988

The chlordiazepoxide/pentylenetetrazol discrimination: characterization of drug interactions and homeostatic responses to drug challenges.

Rats were trained to discriminate chlordiazepoxide (CDP) from pentylenetetrazol (PTZ) in a two-lever food motivated discrimination task. Training drug doses were adjusted until subjects emitted approximately 50% of their responses on each of the two drug-appropriate levers during saline injection tests. Tests that followed injection of CDP/PTZ combinations illustrated a reciprocal antagonism between the two drugs. Saline-injection tests that followed large dose injections of CDP revealed a period of predominantly PTZ-appropriate responding that persisted after the initial period of predominantly CDP-appropriate responding. These data are interpreted to suggest that, unlike some other drugs that have been shown to antagonize the behavioral and CNS effects of benzodiazepines, the interoceptive stimulus generated by PTZ occupies a position opposite to that of CDP along some single affective continuum. In addition, these data suggest that drug/drug (DD) discriminations are capable of characterizing the interactions between training drugs. Finally, the data suggest that the CDP/PTZ discrimination is a sensitive detector of bidirectional shifts in interoceptive stimulus state along the CDP/PTZ continuum.

Animals↗
PubMedDate not supplied

Acute effects of ethanol on recurrent inhibitory circuits of CA1 neurons in vivo.

This study examined the dose-dependent effects of acute ethanol on recurrent inhibitory mechanisms of hippocampal CA1 neurons in anesthetized rats. The effects of micropressure-ejected GABAergic compounds were studied on evoked field responses and recurrent inhibition of CA1 pyramidal neurons. None of the systemic doses of ethanol examined altered recurrent inhibition of CA1 neurons. In contrast, local application of both GABAa and GABAb compounds produced clear changes in evoked field responses and blocked recurrent inhibition. These results suggest that (a) recurrent inhibition in the CA1 region in vivo is resistant to the effects of ethanol, and (b) both GABAergic receptor subtypes modulate recurrent inhibition in the CA1 region in vivo.

Animals↗