Abstract
Summary: Isolated strips of pig renal calyx undergo spontaneous rhythmical changes in tension.Noradrenaline, adrenaline and phenylephrine mediate their stimulatory effects by interaction with α‐adrenoceptors, and isoprenaline its inhibitory effect via β‐adrenoceptors.Acetylcholine exerts a similar excitatory action via muscarinic receptors.Evidence is presented for innervation of the a‐adrenoceptors, although this innervation appears to be relatively sparse.