Hilar Mossy Cells Provide the First Glutamatergic Synapses to Adult-Born Dentate Granule Cells

Adult-generated granule cells (GCs) in the dentate gyrus must establish synapses with preexisting neurons to participate in network activity. To determine the source of early glutamatergic synapses on newborn GCs in adult mice, we examined synaptic currents at the developmental stage when NMDA receptor-mediated silent synapses are first established. We show that hilar mossy cells provide initial glutamatergic synapses as well as disynaptic GABAergic input to adult-generated dentate GCs

Modulation of Ethanol Withdrawal???Induced Anxiety-Like Behavior During Later Withdrawals by Treatment of Early Withdrawals With Benzodiazepine/??-Aminobutyric Acid Ligands

Anxiety states, including those arising during acute or protracted withdrawal periods, may be precipitating factors in alcoholic relapse. Given the cyclical nature of ethanol withdrawal associated with repeated cycles of ethanol intake and abstinence in a pattern that often spans years, meaningful attempts to model ethanol withdrawal–associated anxiety should incorporate cycled ethanol treatments. The studies reported herein examined the effects of γ-aminobutyric acid–modulating drugs on social interaction behavior—an established model of anxiety—in rats exposed to repeated cycles of ethanol treatment and withdrawal

Drug Challenges Reveal Differences in Mediation of Stress Facilitation of Voluntary Alcohol Drinking and Withdrawal-Induced Anxiety in Alcohol-Preferring P Rats

There is controversy over whether exposure to stress precipitates relapse and/or increases alcohol (ethanol) intake. Our laboratory has demonstrated that repeated stress prior to withdrawal from a brief forced exposure to alcohol results in withdrawal-induced anxiety-like behavior. Because anxiety is often regarded as a precipitating factor in relapsing alcoholics, we decided to examine the consequences of stressing alcohol-preferring P rats on both voluntary alcohol drinking and withdrawal-induced anxiety

Similar anxiety-like responses in male and female rats exposed to repeated withdrawals from ethanol

Previous research indicated that male rats exhibited anxiety-like behavior following withdrawal from chronic ethanol exposure. This behavior, as well as other symptoms of withdrawal such as seizure susceptibility, may be sensitized in male rats repeatedly withdrawn from chronic ethanol exposure. Because there are sex differences in some alcohol effects, the present study explored whether male and female rats would respond differently to a course of repeated ethanol withdrawals. Similarly aged male and female rats were exposed to a control liquid diet or a diet containing ethanol (7% w/v). Ethanol-exposed rats had only one 5-day cycle of exposure or three cycles, with 2 days of control diet (CD) between cycles. At 5 h after the final ethanol was removed, the rats were placed as same-sexed pairs in the social interaction test; approximately half of the rats were tested later in the elevated plus maze. Rats withdrawn from ethanol after three cycles exhibited reduced the time spent in social interaction and general activity in the social interaction test and reduced the open and closed arm entries in the elevated plus maze. There were no sex differences in these effects. However, male rats exhibited a small anxiety-like response after one cycle of 5 days’ exposure to ethanol and female rats did not. Thus, there are no sex differences in the three-cycle multiple-withdrawal paradigm, but there may be differences after briefer exposures

Conceptual framework for the etiology of alcoholism: a ?kindling?/stress hypothesis

The rationale for proposing the “kindling”/stress hypothesis is to provide a conceptual basis for the insidious development and maintenance of alcohol abuse

Erratum: Stress Sensitization of Ethanol Withdrawal-Induced Reduction in Social Interaction: Inhibition by CRF-1 and Benzodiazepine Receptor Antagonists and a 5-HT1A–Receptor Agonist

Repeated withdrawals from chronic ethanol sensitize the withdrawal-induced reduction in social interaction behaviors. This study determined whether stress might substitute for repeated withdrawals to facilitate withdrawal-induced anxiety-like behavior. When two 1-h periods of restraint stress were applied at 1-week intervals to rats fed control diet, social interaction was reduced upon withdrawal from a subsequent 5-day exposure to ethanol diet. Neither this ethanol exposure alone nor exposure to three restraint stresses alone altered this measure of anxiety. Further, the repeatedly stressed singly withdrawn rats continued to exhibit a reduction in social interaction 16 days later, upon withdrawal from re-exposure to 5 days of chronic ethanol, consistent with a persistent adaptation by the multiple-stress/withdrawal protocol. Weekly administration of corticosterone in place of stress induced no significant change in social interaction upon withdrawal from the single chronic ethanol exposure, indicative that corticoid release is not responsible for the stress-induced reduction in anxiety-like behavior during withdrawal. In the multiple-withdrawal protocol, stress applied during withdrawal from voluntary ethanol drinking by P-rats facilitated ethanol drinking sufficiently, to induce a withdrawal-induced reduction in social interaction. Administration of a CRF-1 receptor antagonist, a benzodiazepine receptor antagonist, or a 5-HT1A receptor agonist prior to each stress minimized sensitization of the withdrawal-induced reduction in anxiety-like behavior. Since these pharmacological consequences on the induction of anxiety-like behavior following the stress/withdrawal protocol are like those previously seen when these drug treatments were given prior to multiple withdrawals, evidence is provided that repeated stresses and multiple withdrawals sensitize the withdrawal reduction in social interaction by similar central adaptive mechanisms

Baclofen Blocks Expression and Sensitization of Anxiety-Like Behavior in an Animal Model of Repeated Stress and Ethanol Withdrawal

Repeated exposures to forced ethanol diets (EDs) or restraint stress sensitize anxiety-like behavior during a future ethanol withdrawal. The present investigation assessed whether pretreatment of rats with agents targeting receptor systems thought to be important in treating relapse in alcoholic patients would prevent sensitization of anxiety-like behavior

Accentuated Decrease in Social Interaction in Rats Subjected to Repeated Ethanol Withdrawals

Previous work has shown that repeated withdrawals from chronic ethanol exposure can kindle seizures in rodents. In this article, the effects of a three-cycle model of ethanol exposure and withdrawal on the social interaction test of anxiety are summarized

A selective ALDH-2 inhibitor reduces anxiety in rats

CVT-10216 is a highly selective, reversible inhibitor of ALDH-2 that reduces excessive alcohol drinking. Anxiety plays a role in alcoholism. The present study asks whether CVT-10216 has anxiolytic properties, as reflected in social interaction behavior in four unrelated rodent models: endogenous anxiety-like behavior in naïve Fawn-Hooded rats, repeated alcohol-withdrawal-induced anxiety, restraint stress-induced anxiety and drug-induced anxiety. CVT-10216 counteracted anxiety in all models except that produced by the 5-HT2C agonist, mCPP. CVT-10216 exhibited both acute and prophylactic inhibitions of repeated alcohol-withdrawal-induced anxiety. Importantly, anxiogenic behavior induced by the benzodiazepine receptor inverse agonist, DMCM, was counteracted dose-dependently by CVT-10216. Thus, a non-addictive selective inhibitor of ALDH-2 has both anxiolytic and antidipsotropic properties, which may be dependent, in part on the involvement of the GABA–benzodiazepine system

Nerve growth factor (NGF) has novel antidepressant-like properties in rats

Nerve Growth Factor, a neurotrophin, may have other functions, including a role in depressive disorders. The present study sought to determine whether NGF would (1) have antidepressant-like effects and (2) behave similarly to or differently from other well-recognized antidepressants. Over a broad dose-range, NGF reduced the exaggerated swim test immobility exhibited by the Flinders Sensitive Line (FSL) rats, but at a standard dose of 40 ng/ml, it was not as effective as desipramine (DMI, 5 mg/kg). The low social interaction behavior and locomotor activity of the FSL rats were less affected by NGF than was the immobility. Acute treatment with NGF did not induce c-fos expression in brain regions known to be activated by other acute antidepressants. The fact that chronic treatment with DMI blunted the corticosterone response to fluoxetine was replicated in this study. However, chronic treatment with NGF did not alter this response. Similarly, chronic treatment with fluoxetine blunted 5-HT1A and 5-HT2A receptor-mediated responses, whereas chronic treatment with NGF was without effect. Thus, NGF has antidepressant-like effects but does not appear to have biochemical actions typical of other antidepressants