Effects of acetylsalicylic acid on serotonin brain receptor subtypes.

1. The lysine salt of acetyl salicylic acid (ASA) at a dose equivalent to 400 mg/kg of acetyl salicylic acid (ASA) was intraperitoneally administered in rats. 2. After 30 and 120 min ASA did not modify the number of receptors nor the affinity of [3H] 8-OH-DPAT binding sites in pons and cerebral cortex. On the other hand, the receptor number in the cortex membranes decreased significantly using [3H] ketanserin as ligand, while the receptor number in the pontine membranes did not change. 3. These data support the involvement of central 5-HT receptors in the mode of action of ASA.