Table 1. Levels of the endocannabinoids anandamide (AEA, pmol/g) in different brain structures during acute (16 h) and protracted (34 h) nicotine withdrawal phases.

AEA (pmol/g)	16 h		34 h
	Control	Nicotine	Control	Nicotine
PFC	1.69±0.2	1.58±0.3	1.44±0.2	2.38±0.3
NAC	2.51±0.5	2.04±0.4	4.09±1.3	2.54±0.4
Amy	1.59±0.2	2.27±0.3	1.62±0.2	2.62±0.3*
CPU	1.94±0.3	2.08±0.1	1.75±0.1	2.14±0.2
Hippo	4.47±0.6	3.06±0.3*	3.44±0.5#	2.55±0.2
Hypo	4.13±0.4	4.73±1.4	4.69±0.8	8.39±1.3*

Results showed that major changes occurred for AEA particularly in the amygdala, the hypothalamus and the hippocampus. Values represent the mean (±SEM) of subjects previously treated with nicotine compared to controls at respective time points: *p<0.05.^# p<0.05, ^## p<0.01, difference from control group at 16 h time point; ⁺ p<0.05, difference from nicotine group at 16 h time point.