Table 1.

Effect of pharmacological treatments on the colocalization ratio of GIRK2 and PSD95 immunostaining in 21 DIV cultured hippocampal neurons

Treatment	Pharmacological targets	Colocalization ratio
		Mean ± SEM	N
Control		1.01 ± 0.05	94
Morphine	μ/δ/κ-opioid R agonist	1.51 ± 0.04*	66
DAMGO	μ-opioid R agonist	1.09 ± 0.04	20
DPDPE	δ-opioid R agonist	0.94 ± 0.06	19
Met-enkephalin	μ/δ-opioid R agonist	1.21 ± 0.06*	22
Bicuculline	GABAAR antagonist	1.00 ± 0.07	10
AP5 + CNQX	Ionotropic glutamate R antagonists	1.00 ± 0.06*	30
GABA	GABAA/BR agonist	1.12 ± 0.06	48
Morphine +
Naloxone	μ/δ/κ-opioid R antagonist	0.80 ± 0.04	60
Gabazine	GABAAR antagonist	1.60 ± 0.11*	42
SCH50911	GABABR antagonist	1.87 ± 0.10*	46
Gabazine + CGP 35348	GABAA/GABABR antagonists	1.67 ± 0.23*	47
AP5 + CNQX	Ionotropic glutamate R antagonists	1.63 ± 0.06*	32
TTX	Na channel inhibitor	1.67 ± 0.08*	46
PTX	Gαi/o inhibitor	1.83 ± 0.08*	31

Neurons were treated with indicated drugs: morphine (100 μm), DAMGO (1 μm), DPDPE (100 μm), met-enkephalin (10 μm), bicuculline (30 μm), GABA (100 μm), naloxone (100 μm), gabazine (10 μm), gabazine (10 μm), CGP 35348 (10 μm), SCH50911 (50 μm), AP5 (100 μm), CNQX (10 μm), TTX (2 μm), and/or PTX (250 ng/ml). PTX was applied during the last 6 h of the morphine treatment. Values shown are the mean colocalization ratio (±SEM). N, Number of dendritic fields analyzed; R, receptor.

*p < 0.05 versus control paired with drugs groups, one-way ANOVA followed by Bonferroni post hoc test for significance.