Long-term effects of intermittent versus continuous ethanol exposure on hippocampal synapses of the rat

Lundqvist, Claes; Volk, Benedikt; Knoth, Rolf; Alling, Christopher

doi:10.1007/s004010050082

Cited by 3 publications

(6 citation statements)

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“…Investigation of IAA/CAA in other than adult animals is limited : Few articles have explored possible age dependency of IAA/CAA effects, although intermittency has been suggested to be important in fetal exposure studies (see Lundquist et al, 1994, for discussion) and intermittency effects have been reported to be more pronounced in adolescent than adult C57 mice (Melendez, 2011). There is also some initial evidence that consequences of IAA and CAA may differ in the aged brain from that of the adult brain (Reynolds et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…A couple of other studies have focused on regions of the nervous system differentially affected by IAA and CAA. Lundquist and colleagues (1994) gave male W rats IAA (3 g/kg EtOH intraperitoneally 2 times/d for ~1 month) or CAA (20% EtOH in drinking water [1 bottle only available] for ~1 month). In this study, only rats exposed to IAA exhibited a reduction in number of synapses in the CA3 region of the hippocampus (HPC) , even though total EtOH exposure was greater in the CAA than IAA group (Lundquist et al, 1994).…”

Section: Potential Neurobiological Contributors To Iaa/caa Differencesmentioning

confidence: 99%

“…Lundquist and colleagues (1994) gave male W rats IAA (3 g/kg EtOH intraperitoneally 2 times/d for ~1 month) or CAA (20% EtOH in drinking water [1 bottle only available] for ~1 month). In this study, only rats exposed to IAA exhibited a reduction in number of synapses in the CA3 region of the hippocampus (HPC) , even though total EtOH exposure was greater in the CAA than IAA group (Lundquist et al, 1994). Of course, interpretation of these data in terms of IAA/CAA differences is complicated by the different routes of EtOH exposure used between the groups.…”

Section: Potential Neurobiological Contributors To Iaa/caa Differencesmentioning

confidence: 99%

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Timing Eclipses Amount: The Critical Importance of Intermittency in Alcohol Exposure Effects

Spear

2020

Alcoholism Clin & Exp Res

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Frequency and duration of ethanol (EtOH) exposures influence the consequences of those experiences, with evidence building from basic science studies in rats and mice that intermittent alcohol access (IAA) typically produces a greater escalation of EtOH intake than more continuous alcohol access (CAA). IAA also better simulates human use patterns where alcohol levels typically clear from the body between periods of use. A variety of mechanisms have been proposed to contribute to the enhanced intake of EtOH induced by IAA, including a possible attenuation in the aversive effects of EtOH, although further studies are needed to address this and other possibilities. Neural differences include indications of an IAA-associated increase in NR2B receptors that is not evident with CAA; although little studied, alterations in other neural and neurotransmitter systems are evident as well. Many gaps in understanding of IAA/CAA effects remain. Further work is needed to characterize neural mechanisms underlying these effects, consequences of IAA/CAA on EtOH effects beyond intake, and the impact of stress and environmental variables on these differences. IAA/CAA studies to date have also largely been limited to males and to adult animals, and hence, more studies examining IAA/CAA across sex and age are needed. Such additional work is essential to determine unique contributors to IAA-induced elevations in EtOH intake that may provide important insights for the development of new prevention/intervention strategies for heavy alcohol use and abuse.

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Section: Discussionmentioning

confidence: 99%

Section: Potential Neurobiological Contributors To Iaa/caa Differencesmentioning

confidence: 99%

Section: Potential Neurobiological Contributors To Iaa/caa Differencesmentioning

confidence: 99%

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Timing Eclipses Amount: The Critical Importance of Intermittency in Alcohol Exposure Effects

Spear

2020

Alcoholism Clin & Exp Res

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“…The ethanol-withdrawal syndrome and excitotoxic mechanisms related to it may contribute to ethanolinduced neurodegeneration. Intermittent ethanol exposure with repeated withdrawal periods has been suggested to be more damaging to neurons than continuous exposure (Lundqvist et al, 1994(Lundqvist et al, , 1995Lundqvist, 1997). Previously, ageing has been reported to increase the severity of the ethanol withdrawal syndrome (Maier and Pohorecky, 1989).…”

Section: Discussionmentioning

confidence: 99%

Effects of Ageing and Intermittent Ethanol Exposure on Rat Locus Coeruleus and Ethanol-Withdrawal Symptoms

Riihioja

Jaatinen²,

Haapalinna³

et al. 1999

Alcohol and Alcoholism

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In this study, the effects of ethanol and age on the morphology of the locus coeruleus (LC) and on the severity of ethanol-withdrawal symptoms were studied during a 5-week intermittent ethanol exposure. Young (3-4 months) and old (29-30 months) male Wistar rats were given highly intoxicating doses of ethanol by intragastric intubations for 4 days, followed by a 3-day ethanol-withdrawal period. This 7-day cycle of ethanol exposure and withdrawal was repeated five times. A non-treated group and a sucrose-fed group of both ages were used as control groups. The severity of ethanol-withdrawal symptoms (rigidity, tremor, irritability, hypoactivity) was rated up to 62 h after the last dose of ethanol. The intoxication level was higher in the old, compared with the young, rats, despite the smaller doses of ethanol given to the old animals. There was no significant difference between the age groups in the severity of the ethanol-withdrawal syndrome. The LC quantitative studies were performed using unbiased stereological methods. The results showed that there was no difference between the age groups in the LC total neuron numbers of the non-treated control groups. The 5-week intermittent ethanol exposure significantly reduced the LC neuron numbers and LC neuronal density in the old ethanol-exposed animals, compared with the sucrose-fed control animals. In the young rats, the ethanol-induced neuron loss did not reach statistical significance. According to the ANCOVA, the difference in the ethanol-induced LC neuronal loss between the age groups may be due to the difference in the intoxication levels. Interestingly, the sucrose intubations were also found to decrease the LC neuronal numbers in the young rats, compared with the non-treated young control group. It was concluded that ageing did not significantly affect the severity of ethanol-withdrawal symptoms or ethanol-induced loss of LC neurons in Wistar rats.

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“…A key feature of alcohol use disorders (AUDs) is the transition from recreational to escalated use that persists despite adverse consequences. A similar phenomenon exists in rodent models, as repeated, intermittent access to ethanol (EtOH) drives escalation of voluntary intake of EtOH, particularly at higher concentrations which are often treated as aversive in naïve rats (Carnicella et al, 2014, Simms et al, 2008, Rosenwasser et al, 2013, Lundqvist et al, 1994). Intermittent-EtOH access and/or presentation of EtOH-predictive cues can sufficiently escalate intake above that observed in continuous-access paradigms, mimicking moderate to excessive EtOH drinking behaviors in humans (Carnicella et al, 2014) and this occurs whether EtOH is presented intermittently across days (Simms et al, 2008), or within session (Tomie et al, 2006, Loney and Meyer, 2018).…”

Section: Introductionmentioning

confidence: 89%

Escalation of alcohol intake is associated with regionally decreased insular cortex activity but not associated with changes in taste quality

Mukherjee

Paladino

McSain

et al. 2022

Preprint

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Background: Intermittent access to ethanol (EtOH) drives persistent escalation of intake and rapid transition from moderate to compulsive-like drinking. Intermittent EtOH drinking may facilitate escalation in part by altering aversion-sensitive neural substrates, such as the insular cortex (IC), thus driving greater approach toward stimuli previously treated as aversive. Methods: We conducted a series of experiments in rats to examine behavioral and neural responses associated with escalation of EtOH intake. First, taste reactivity analyses quantified the degree that intermittent brief-access ethanol exposure (BAEE) alters sensitivity to the aversive properties of EtOH. Next, we determined whether pharmacological IC inhibition facilitated EtOH escalation. Finally, given that IC is primary gustatory cortex, we employed psychophysical paradigms to assess whether escalation of EtOH intake induced changes in EtOH taste. These paradigms measured changes in sensitivity to the intensity of EtOH taste and whether escalation shifts the salient taste quality of EtOH by measuring the degree that the taste of EtOH generalized to a sucrose-like (sweet) or quinine-like (bitter) percept. Results: We found a near complete loss of aversive oromotor responses in EtOH-exposed relative to -naive rats. Additionally, we observed significantly reduced expression of EtOH-induced c-Fos expression in the posterior IC in exposed rats relative to naive rats. Inhibition of the IC resulted in a modest, but statistically reliable increase in acceptance of higher EtOH concentrations in naive rats. Finally, we found no evidence of changes in the psychophysical assessment of the taste of EtOH in exposed, relative to naive, rats. Conclusions: Our results demonstrate that neural activity within the IC adapts following escalation of EtOH intake in a manner that correlates with reduced sensitivity to the aversive hedonic properties of EtOH. These data further establish that IC may be driving exposure-induced escalations in EtOH intake and directly contributing to development of compulsive-like EtOH drinking.

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Long-term effects of intermittent versus continuous ethanol exposure on hippocampal synapses of the rat

Cited by 3 publications

References 0 publications

Timing Eclipses Amount: The Critical Importance of Intermittency in Alcohol Exposure Effects

Timing Eclipses Amount: The Critical Importance of Intermittency in Alcohol Exposure Effects

Effects of Ageing and Intermittent Ethanol Exposure on Rat Locus Coeruleus and Ethanol-Withdrawal Symptoms

Escalation of alcohol intake is associated with regionally decreased insular cortex activity but not associated with changes in taste quality

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