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GABA A receptors are involved in the analgesic effects of morphine microinjected into the central nucleus of the amygdala
Author(s) -
Rashvand Mina,
Khajavai Ali,
Parviz Mohsen,
Hasanein Parisa,
Keshavarz Mansoor
Publication year - 2014
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/1440-1681.12223
Subject(s) - muscimol , bicuculline , opioidergic , morphine , microinjection , chemistry , pharmacology , gabaa receptor , agonist , gaba receptor antagonist , damgo , receptor , analgesic , μ opioid receptor , inhibitory postsynaptic potential , endocrinology , opioid , medicine , (+) naloxone , opioid receptor , biochemistry
Summary The central nucleus of the amygdala ( C e A ) has an important role in pain perception and analgesia. Opioid and GABA A receptors, which are both involved in pain modulation, are found in high concentration in the C e A . The present study was designed to examine the interaction of opioidergic and GABA ergic systems in the C e A during modulation of acute thermal pain. In the present study, different doses of morphine (25, 50 and 100 μg/rat), either alone or after 5 min pretreatment with the selective GABA A receptor agonist muscimol (60 ng/rat) or the selective GABA A receptor antagonist bicuculline (50 ng/rat), were injected bilaterally into the C e A of each rat. Tail‐flick latencies ( TFL ) were measured every 5 min for 60 min. The results revealed that microinjection of morphine into the C e A significantly increased TFL in a dose‐dependent manner. Microinjection of bicuculline or muscimol in combination with morphine into the C e A increased and decreased TFL , respectively. It seems that morphine in the C e A facilitates the function of descending inhibitory systems by interacting with the activity of local GABA A receptors.