title: Theory of step-wise excitation in gastropod heart.
mesh_terms: D000588:Amines / Q000494:pharmacology*; D000818:Animals; D002395:Catecholamines / Q000032:analysis; D005453:Fluorescence; D006321:Heart / Q000187:drug effects* / Q000502:physiology*; D006325:Heart Atria; D006329:Heart Conduction System; D009119:Muscle Contraction / Q000187:drug effects; D009206:Myocardium / Q000737:chemistry / Q000201:enzymology; D009711:Nucleotides / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D012908:Snails; D009435:Synaptic Transmission; D014166:Transferases / Q000378:metabolism
chemical_list: D000588:Amines; D002395:Catecholamines; D009711:Nucleotides; D011687:Purines; D011743:Pyrimidines; D014166:Transferases