Figure 3. log dose-response curves showing the effects of αβ-MeATP.

Results from individual experiments illustrating the effects of αβ-MeATP on heart rate (A), apnoea (B) and hyperventilation (C), before (^) and after (•) the purinoceptor antagonist PPADS (17 μmol (kg body wt)⁻¹ i.v.) which reduced the bradycardia and apnoea components of agonist-induced responses, whereas the hyperventilation component was unaffected or even enhanced by PPADS. Apparent ED₅₀ values were estimated from the log dose-response plots.