Lack of interaction of endocannabinoids and 5-HT3 neurotransmission in associative fear circuits of the amygdala: Evidence from electrophysiological and behavioural experiments

HOFELMANN, D., B. DI BENEDETTO, S. C. AZAD, Vincenzo MICALE, C.T. WOTJAK and G. RAMMES. Lack of interaction of endocannabinoids and 5-HT3 neurotransmission in associative fear circuits of the amygdala: Evidence from electrophysiological and behavioural experiments. Brain Research. Amsterdam: Elsevier, 2013, vol. 1527, Aug, p. 47-56. ISSN 0006-8993. Available from: https://dx.doi.org/10.1016/j.brainres.2013.06.011.

Basic information

• Original name: Lack of interaction of endocannabinoids and 5-HT3 neurotransmission in associative fear circuits of the amygdala: Evidence from electrophysiological and behavioural experiments
• Authors: HOFELMANN, D. (276 Germany), B. DI BENEDETTO (276 Germany), S. C. AZAD (276 Germany), Vincenzo MICALE (380 Italy, guarantor, belonging to the institution), C.T. WOTJAK (276 Germany) and G. RAMMES (276 Germany).
• Edition: Brain Research, Amsterdam, Elsevier, 2013, 0006-8993.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 30000 3. Medical and Health Sciences
• Country of publisher: Netherlands
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 2.828
• RIV identification code: RIV/00216224:14740/13:00072700
• Organization unit: Central European Institute of Technology
• Doi: http://dx.doi.org/10.1016/j.brainres.2013.06.011
• UT WoS: 000324225400005
• Keywords in English: CB1; 5-HT3; Amygdala; Fear conditioning; Slice; IPSC
• Tags: ok, rivok
• Tags: International impact, Reviewed

Abstract

Both the serotonergic and the endocannabinoid system play a major role in mediating fear and anxiety. In the basolateral amygdala (BLA) it has been shown that the cannabinoid receptor 1 (CB1) is highly co-expressed with 5-HT3 receptors on GABAergic intemeurons suggesting that 5-HT3 receptor activity modulates CB1-mediated effects on inhibitory synaptic transmission. In the present study, we investigated the possible interactions of CB1 and 5-HT3-mediated neuronal processes in the BLA using electrophysiological and behavioural approaches. Whole-cell patch-clamp recordings were performed in coronal brain slices of mice. Electric stimuli were delivered to the lateral amygdala to evoke GABA(A) receptor-mediated inhibitory postsynaptic currents (GABA(A)-eIPSCs) in the BLA. The induction of LTDi, a CB1-mediated depression of inhibitory synaptic transmission, was neither affected by the 5-HT3 antagonists ondansetron (OND; 20 mu M) and tropisetron (Trop; 50 nM) nor by the 5-HT3 agonists SR57227A (10 mu M). In auditory fear conditioning tests, mice treated with SR57227A (3.0 mg/kg i.p.) showed sustained freezing, whereas treatment with Trop (1.0 mg/kg i.p.) decreased the expression of conditioned fear. These effects were overruled by the CB1 antagonist rimonabant (RIM; 3.0 mg/kg), which caused increased freezing with or without co-treatment with Trop. In summary, these experiments do not support a functional interaction between CB1 and 5-HT3 receptors at the level of GABA neurotransmission in the BLA nor in terms of fear regulation. (C) 2013 Elsevier B.V. All rights reserved.

Links

• ED1.1.00/02.0068, research and development project: Name: CEITEC - central european institute of technology