The effects of VR1 antagonism on capsaicin-induced (left panels) and anandamide-induced (right panels) changes in respiratory minute volume (RMV, ml min−1) in the anaesthetized rat. Values are shown as mean±s.e.mean before and after (a, b) ruthenium red (1 mg kg−1 i.a.) (n=4), (c, d) capsazepine (1 mg kg−1 i.a.) (n=4), and (e, f) capsaicin pre-treatment (200 nmoles i.a.) (n=5 – 6). *P<0.05, **P<0.01 vs before antagonist; paired Student's t-test.