TABLE 2.

Cholesterol level affects opioid signaling in primary hippocampal cultures

	AC Inhibition by Morphine		AC Inhibition by Fentanyl
	KI (nM)	Maximum inhibition (%)	KI (pM)	Maximum inhibition (%)
Control	20.3 ± 2.3	35 ± 2.9	175 ± 26	29 ± 2.7
DMSO	24.0 ± 3.4	31 ± 3.3	198 ± 22	31 ± 2.4
Simvastatin	55.7 ± 4.1*	14 ± 2.7*	432 ± 37*	11 ± 1.9*
Simva+Chol	21.8 ± 2.8	30 ± 2.5	212 ± 21	27 ± 2.9
Cholesterol	16.3 ± 2.1*	47 ± 3.1*	122 ± 18*	41 ± 3.4*
DPDMP	34.6 ± 3.2*	22 ± 2.6*	317 ± 27*	21 ± 3.0*

The primary neuron cultures were treated with PBS (Control), DMSO (DMSO), 0.5 μM simvastatin (Simvastatin), 0.5 μM simvastatin with 40 ng/ml cholesterol (Simva+Chol), 40 ng/ml cholesterol (Cholesterol), or 20 μM DPDMP (DPDMP) for 24 h. AC inhibition was carried out and analyzed as in Table 1. There were also significant differences between the Simvastatin and DPDMP groups. Asterisks represent the significant difference from Control.