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Reich N, Hölscher C. Beyond Appetite: Acylated Ghrelin As A Learning, Memory and Fear Behavior-modulating Hormone. Neurosci Biobehav Rev 2022; 143:104952. [DOI: 10.1016/j.neubiorev.2022.104952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 04/27/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022]
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Quadir SG, Arleth GM, Jahad JV, Echeveste Sanchez M, Effinger DP, Herman MA. Sex differences in affective states and association with voluntary ethanol intake in Sprague-Dawley rats. Psychopharmacology (Berl) 2022; 239:589-604. [PMID: 35044485 DOI: 10.1007/s00213-021-06052-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/27/2021] [Indexed: 01/11/2023]
Abstract
Alcohol use disorders (AUDs) are a major problem across the USA. While AUD remains a complex human condition, it is difficult to isolate the directionality of anxiety and ethanol (EtOH) drinking from outside influences. The present study sought to investigate the relationship between affective states and EtOH intake using male and female Sprague-Dawley rats. Using complementary tests of anxiety- and depressive-like behavior, we found sex- and test-specific differences in basal affective behavior such that females displayed enhanced anxiety-like behavior in the splash test and males displayed enhanced anxiety-like behavior in the novelty-suppressed feeding test. Although, there were no sex differences in EtOH intake and no correlation between baseline anxiety-like behavior and subsequent EtOH intake, we did find that depressive-like behavior predicted future EtOH intake in female rats only. In addition, we observed an increase in depressive-like behavior is male rats in both the water and EtOH drinking groups (compared to baseline levels). Furthermore, post-drinking anxiety-like behavior, but not depressive-like behavior predicted subsequent EtOH intake in female rats. Lastly, we found a history of EtOH intake decreased pain thresholds in male and female rats, but increased anxiety-like and depressive-like behavior was associated with decreased thermal sensitivity only in EtOH-drinking males. Together, these experiments provide important information on the complex interaction between negative affect and EtOH intake and how these two contexts reciprocally do, or do not, influence each other in a sex-specific manner.
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Affiliation(s)
- S G Quadir
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - G M Arleth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - J V Jahad
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - M Echeveste Sanchez
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - D P Effinger
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - M A Herman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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Fasting enhances extinction retention and prevents the return of fear in humans. Transl Psychiatry 2018; 8:214. [PMID: 30301955 PMCID: PMC6177454 DOI: 10.1038/s41398-018-0260-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 08/02/2018] [Accepted: 09/10/2018] [Indexed: 01/24/2023] Open
Abstract
Fear is prone to return following extinction that is the basis of exposure therapy for fear-related disorders. Manipulations that enhance the extinction process can be beneficial for treatment. Animal studies have shown that fasting or caloric restriction can enhance extinction and inhibit the return of fear. The present study examined the effects of fasting on fear acquisition, extinction, and the return of fear in humans. One hundred and twenty-five male participants were randomized into a fasting group and food group and exposed to a Pavlovian fear conditioning paradigm. Changes in plasma cortisol and ghrelin levels were examined using enzyme-linked immunosorbent assays. One-night fasting had no effect on fear acquisition but enhanced fear extinction retention and prevented the return of fear, and this effect persisted for at least 6 months. This procedure was also effective for remote fear memory. Plasma ghrelin levels were elevated after fasting and had a negative relationship with the fear response in spontaneous recovery test. However, overnight fasting did not affect cortisol levels. These findings indicate that fasting enhances extinction retention and prevents the return of fear, without influencing fear memory formation. We propose that this novel procedure may open new avenues for promoting extinction-based therapies for fear-related disorders.
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Abstract
Three experiments explored the link between reward shifts and latent inhibition (LI). Using consummatory procedures, rewards were either downshifted from 32% to 4% sucrose (Experiments 1-2), or upshifted from 4% to 32% sucrose (Experiment 3). In both cases, appropriate unshifted controls were also included. LI was implemented in terms of fear conditioning involving a single tone-shock pairing after extensive tone-only preexposure. Nonpreexposed controls were also included. Experiment 1 demonstrated a typical LI effect (i.e., disruption of fear conditioning after preexposure to the tone) in animals previously exposed only to 4% sucrose. However, the LI effect was eliminated by preexposure to a 32%-to-4% sucrose devaluation. Experiment 2 replicated this effect when the LI protocol was administered immediately after the reward devaluation event. However, LI was restored when preexposure was administered after a 60-min retention interval. Finally, Experiment 3 showed that a reward upshift did not affect LI. These results point to a significant role of negative emotion related to reward devaluation in the enhancement of stimulus processing despite extensive nonreinforced preexposure experience.
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Huang CC, Chou D, Yeh CM, Hsu KS. Acute food deprivation enhances fear extinction but inhibits long-term depression in the lateral amygdala via ghrelin signaling. Neuropharmacology 2015; 101:36-45. [PMID: 26384653 DOI: 10.1016/j.neuropharm.2015.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/11/2015] [Accepted: 09/14/2015] [Indexed: 10/23/2022]
Abstract
Fear memory-encoding thalamic input synapses to the lateral amygdala (T-LA) exhibit dynamic efficacy changes that are tightly correlated with fear memory strength. Previous studies have shown that auditory fear conditioning involves strengthening of synaptic strength, and conversely, fear extinction training leads to T-LA synaptic weakening and occlusion of long-term depression (LTD) induction. These findings suggest that the mechanisms governing LTD at T-LA synapses may determine the behavioral outcomes of extinction training. Here, we explored this hypothesis by implementing food deprivation (FD) stress in mice to determine its effects on fear extinction and LTD induction at T-LA synapses. We found that FD increased plasma acylated ghrelin levels and enhanced fear extinction and its retention. Augmentation of fear extinction by FD was blocked by pretreatment with growth hormone secretagogue receptor type-1a antagonist D-Lys(3)-GHRP-6, suggesting an involvement of ghrelin signaling. Confirming previous findings, two distinct forms of LTD coexist at thalamic inputs to LA pyramidal neurons that can be induced by low-frequency stimulation (LFS) or paired-pulse LFS (PP-LFS) paired with postsynaptic depolarization, respectively. Unexpectedly, we found that FD impaired the induction of PP-LFS- and group I metabotropic glutamate receptor agonist (S)-3,5-dihydroxyphenylglycine (DHPG)-induced LTD, but not LFS-induced LTD. Ghrelin mimicked the effects of FD to impair the induction of PP-LFS- and DHPG-induced LTD at T-LA synapses, which were blocked by co-application of D-Lys(3)-GHRP-6. The sensitivity of synaptic transmission to 1-naphthyl acetyl spermine was not altered by either FD or ghrelin treatment. These results highlight distinct features of fear extinction and LTD at T-LA synapses.
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Affiliation(s)
- Chiung-Chun Huang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Dylan Chou
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Che-Ming Yeh
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Kuei-Sen Hsu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
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