Effect of Intra-Amygdala Injection of Nicotine and GABA Receptor Agents on Anxiety-Like Behaviour in Rats

Abstract

There is evidence that both cholinergic and GABAergic systems are involved in the neurobiology of anxiety. In the present study, we investigated the effects and interaction of nicotinic and GABAergic systems in the central amygdala of rats, using the elevated plus maze test of anxiety. Bilateral administration of nicotine (1 and 2 µg/rat; 1 µl/rat; 0.5 µl/rat in each side) into the central amygdala (intra-CeA) induced an anxiogenic-like effect, shown by specific decreases in the percentage of open-arm time (%OAT) and percentage of open arm entries (%OAE). Intra-CeA injection of mecamylamine, a selective nicotine acetylcholine receptor antagonist (20, 30 and 50 ng/rat; 1 µl/rat; 0.5 µl/rat in each side) produced significant anxiolytic-like behaviour. The intra-CeA injection of the GABA_A receptor agonist muscimol (0.25, 0.5 and 0.75 µg/rat; 1 µl/rat; 0.5 µl/rat in each side) decreased %OAT and %OAE, indicating anxiogenic-like behaviour. However, intra-CeA administration of the GABA_A receptor antagonist bicuculline (0.25, 0.5 and 1 µg/rat; 1 µl/rat; 0.5 µl/rat in each side) produced significant anxiolytic-like behaviour. Nicotine in a subeffective dose (0.25 µg/rat) when co-administered with muscimol did not significantly increase the anxiety behaviour. An effective dose of nicotine (2 µg/rat) in combination with bicuculline (0.25, 0.5 and 1 µg/rat) had no interaction on %OAT, %OAE and locomotor activity. It can be concluded that in the central amygdala, the GABAergic system is not involved in the anxiogenic response to nicotine.

Original article Involvement of D 2 /D 2 dopamine antagonists upon open-arms exploratory behaviours induced by intra-nucleus accumbens shell administration of N-methyl-D-aspartate

“…Between EPM sessions and after each rat the maze was cleaned with distilled water. The obtained data were used to calculate: a) % OAT (the ratio of time spent in open arms to the time spent in all arms ×100); b) % OAE (the ratio of entries into open arms to total entries ×100) [55,97,98], and c) the total closed and open arm entries were considered as a relatively pure index for the locomotor activity [93,95].…”

Prenatal exposure to lps leads to long‐lasting physiological consequences in male offspring

“…For testing purpose, male offspring were placed individually in the center portion of the plus-maze, facing one of the open arms. The observer measured: (1) (Solati, Zarrindast, & Salari, 2010;Zarrindast, Solati, Oryan, & Parivar, 2008). All testing was conducted between 13:00 and 16:00 hr.…”

Activation of GABAA receptors in the medial prefrontal cortex produces an anxiolytic-like response

“…GABAergic neurons are one of the most important components prevalent in all areas of the brain and its neurotransmission is vital for brain function (5). Although GABA plays a major role in the modulation of virtually all cognitive and behavioural processes, several basic and clinical studies have particularly highlighted the role of this neurotransmitter in the central modulation of anxiety and stress responses (6)(7)(8)(9).…”