Figure 8.

Effect of a D₁-like receptor agonist and galanin on K⁺-induced [³H]ACh release from ventral hippocampal synaptosomes. a, Dopamine receptors were activated (right column) by preincubation with the agonist SKF 38393 before addition of galanin. b, Galanin receptors were activated (right column) by preincubation with galanin before addition of SKF 38393. Ordinates represent the S2/S1 ratios as percentage of the control value in the same experiments (see Materials and Methods). Drug conditions during S1 and S2 are indicated below each bar. In the ordinates, 100% represents the S2/S1 ratio in the absence of the test drug, i.e., in the absence of galanin (a) or in the absence of SKF 38393 (b), using the same synaptosomal batch. An S2/S1 ratio close to 100% represents, therefore, absence of effect of the test drug (galanin in a or SKF 38393 in b). Values are mean ± SEM (n = 3–6). In a, 100% corresponds to 0.76 ± 0.046, and in b it corresponds to 0.70 ± 0.029. The presence of SKF 38393 (a) or of galanin (b) during S1 and S2 did not significantly affect S2/S1 ratios compared with those obtained in the absence of any drug. *p < 0.05; NS, p > 0.05 (Student's t test).