Figure 6.
Modulation of the uptake and release of [3H]glutamate in striatal synaptosomes of wild-type and CB1 receptor knock-out (-/-) mice. A, Properties of [3H]glutamate release in the rat and the two mouse types. The release is slightly but significantly altered in the CB1 -/- mouse compared with the wild-type mouse. B, WIN55212-2 inhibits the uptake of [3H]glutamate in both mouse types. C, D, WIN55212-2 (although less potently and effectively) and CP55940 attenuate the Ca2+-dependent, 25 mm K+-evoked release of [3H]glutamate from the wild-type CD-1 and the CB1 null-mutant mouse striatal synaptosomes. In the presence of AM251, given 20 min before SK1 and being present in all solutions used, the SK2/SK1 ratio significantly diminished, indicating differences between the CD-1 mouse and the Wistar rat, although the likely time-dependent underlying mechanism is unclear. No further inhibition of [3H]glutamate release by WIN55212-2 (20 μm) is observed in the presence of AM251 either in wild-type or CB1-/-mice. *p < 0.05; **p < 0.01; ***p < 0.001 versus drug-freec ontrols (CTRL). n ≥ 8 for all data points.