Effect of the 5-HT1A receptor agonist buspirone and 5-HT1B/D agonist sumatriptan on fundic compliance. Buspirone (Panel A, pre-drug: black line, post-drug: grey line, 0.15 mg/kg, i.v.) initially increased intercrystal distance suggesting it increased fundic size but did not subsequently alter compliance. Sumatriptan (0.1 mg/kg, i.v.) initially decreased intercrystal distance suggesting it increased fundic size but, in contrast with buspirone, subsequently increased fundic compliance (Panel B, pre drug: black line, post drug: grey line).