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Cannabinoid CB1 receptors of the rat central amygdala mediate anxiety-like behavior: interaction with the opioid system.
Behav Pharmacol. 2008 Oct; 19(7):716-23.BP

Abstract

Cannabinoids, which are the active compounds of marijuana, produce some pharmacological effects similar to the opioids. In addition, there are functional interactions between the cannabinoid and opioid systems. In this study, we investigated the effects of intraperitoneal (i.p.) injection of opioid drugs on responses induced by intracentral amygdala (intra-CeA) microinjection of cannabinoid CB1 receptor agents in rats, using the elevated plus maze test of anxiety. I.p. injection of morphine (6 and 9 mg/kg) 30 min before testing, increased the percentage open arm time (%OAT) and the percentage open arm entries (%OAE), but not locomotor activity, showing an anxiolytic-like response. I.p. administration of the opioid receptor antagonist, naloxone (1 mg/kg) 15 min before testing, significantly reduced %OAT, but not %OAE and locomotor activity. The drug, however, tended to decrease locomotor activity. Intra-CeA administration of arachidonylcyclopropylamide (ACPA, an agonist shown to selectively activate CB1 receptors; 1.25 and 5 ng/rat) increased %OAT and %OAE but not locomotor activity, indicating an anxiolytic-like response. Coadministration of morphine (6 mg/kg, i.p.) plus ACPA (0.125 ng/rat, intra-CeA) increased the anxiolytic-like response. Administration of naloxone reversed the effects of intra-CeA injection of ACPA. Intra-CeA administration of the cannabinoid CB1 receptor antagonist, AM251 (2.5, 25, and 100 ng/rat) did not alter %OAT and %OAE, but the higher doses of the drug (25 and 100 ng/rat) reduced locomotor activity. Coadministration of morphine (6 mg/kg) or naloxone (0.1 mg/kg) with AM251 showed an anxiolytic-like response. In conclusion, the results may indicate an anxiolytic-like effect for cannabinoid CB1 receptors of the CeA and the existence of an interaction between the cannabinoid and the opioid systems in the modulation of anxiety.

Authors+Show Affiliations

Department of Pharmacology, School of Medicine and Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.irNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18797248

Citation

Zarrindast, Mohammad-Reza, et al. "Cannabinoid CB1 Receptors of the Rat Central Amygdala Mediate Anxiety-like Behavior: Interaction With the Opioid System." Behavioural Pharmacology, vol. 19, no. 7, 2008, pp. 716-23.
Zarrindast MR, Sarahroodi S, Arzi A, et al. Cannabinoid CB1 receptors of the rat central amygdala mediate anxiety-like behavior: interaction with the opioid system. Behav Pharmacol. 2008;19(7):716-23.
Zarrindast, M. R., Sarahroodi, S., Arzi, A., Khodayar, M. J., Taheri-Shalmani, S., & Rezayof, A. (2008). Cannabinoid CB1 receptors of the rat central amygdala mediate anxiety-like behavior: interaction with the opioid system. Behavioural Pharmacology, 19(7), 716-23. https://doi.org/10.1097/FBP.0b013e3283123c83
Zarrindast MR, et al. Cannabinoid CB1 Receptors of the Rat Central Amygdala Mediate Anxiety-like Behavior: Interaction With the Opioid System. Behav Pharmacol. 2008;19(7):716-23. PubMed PMID: 18797248.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cannabinoid CB1 receptors of the rat central amygdala mediate anxiety-like behavior: interaction with the opioid system. AU - Zarrindast,Mohammad-Reza, AU - Sarahroodi,Shadi, AU - Arzi,Ardeshir, AU - Khodayar,Mohammad Javad, AU - Taheri-Shalmani,Saba, AU - Rezayof,Ameneh, PY - 2008/9/18/pubmed PY - 2009/1/24/medline PY - 2008/9/18/entrez SP - 716 EP - 23 JF - Behavioural pharmacology JO - Behav Pharmacol VL - 19 IS - 7 N2 - Cannabinoids, which are the active compounds of marijuana, produce some pharmacological effects similar to the opioids. In addition, there are functional interactions between the cannabinoid and opioid systems. In this study, we investigated the effects of intraperitoneal (i.p.) injection of opioid drugs on responses induced by intracentral amygdala (intra-CeA) microinjection of cannabinoid CB1 receptor agents in rats, using the elevated plus maze test of anxiety. I.p. injection of morphine (6 and 9 mg/kg) 30 min before testing, increased the percentage open arm time (%OAT) and the percentage open arm entries (%OAE), but not locomotor activity, showing an anxiolytic-like response. I.p. administration of the opioid receptor antagonist, naloxone (1 mg/kg) 15 min before testing, significantly reduced %OAT, but not %OAE and locomotor activity. The drug, however, tended to decrease locomotor activity. Intra-CeA administration of arachidonylcyclopropylamide (ACPA, an agonist shown to selectively activate CB1 receptors; 1.25 and 5 ng/rat) increased %OAT and %OAE but not locomotor activity, indicating an anxiolytic-like response. Coadministration of morphine (6 mg/kg, i.p.) plus ACPA (0.125 ng/rat, intra-CeA) increased the anxiolytic-like response. Administration of naloxone reversed the effects of intra-CeA injection of ACPA. Intra-CeA administration of the cannabinoid CB1 receptor antagonist, AM251 (2.5, 25, and 100 ng/rat) did not alter %OAT and %OAE, but the higher doses of the drug (25 and 100 ng/rat) reduced locomotor activity. Coadministration of morphine (6 mg/kg) or naloxone (0.1 mg/kg) with AM251 showed an anxiolytic-like response. In conclusion, the results may indicate an anxiolytic-like effect for cannabinoid CB1 receptors of the CeA and the existence of an interaction between the cannabinoid and the opioid systems in the modulation of anxiety. SN - 0955-8810 UR - https://www.unboundmedicine.com/medline/citation/18797248/Cannabinoid_CB1_receptors_of_the_rat_central_amygdala_mediate_anxiety_like_behavior:_interaction_with_the_opioid_system_ L2 - https://doi.org/10.1097/FBP.0b013e3283123c83 DB - PRIME DP - Unbound Medicine ER -