title: Pharmacological effects of two cytolysins isolated from the sea anemone Stichodactyla helianthus.
abstract: Sticholysins I and II (St I/II) are cytolysins purified from the sea anemone Stichodactyla helianthus. In this study, we show their pharmacological action on guinea-pig and snail models in native and pH-denatured conditions in order to correlate the pharmacological findings with the pore-forming activity of both isoforms. In guinea-pig erythrocytes (N=3), St II possessed higher haemolytic activity in comparison with St I and this activity was lost at an alkaline pH. In molluscan central neurons (N=30), they irreversibly decreased the amplitude of the cholinergic response; St I (EC (50) 0.6 micromolL (-1)) was more potent than St II (EC50 > 6.6 micromolL (-1)) and they both increased the duration of the action potential; these effects were absent at an alkaline pH. In guinea-pig isolated atrium (N=25), both increased the amplitude of the contraction force, but St II was more potent than St I (EC (50) 0.03 micromolL (-1) and 0.3 micromolL (-1), respectively) and this effect persisted at an alkaline pH. In summary, both cytolysins have neuroactive and cardioactive properties. The main mechanism in molluscan neurons seems to be associated with the cytolytic activity of these molecules, whereas inguinea-pig atrium, the existence of an additional pharmacological mechanism might be contributing to the observed effect.
authors.affiliation: Centro de Bioproductos Marinos, Loma y 37, Plaza, CP 10600, La Habana, Cuba. cebimar@infomed.sld.cu
authors.forename: T
authors.initials: T
authors.lastname: García
authors.forename: D
authors.initials: D
authors.lastname: Martinez
authors.forename: A
authors.initials: A
authors.lastname: Palmero
authors.forename: C
authors.initials: C
authors.lastname: Soto
authors.forename: M
authors.initials: M
authors.lastname: Tejuca
authors.forename: F
authors.initials: F
authors.lastname: Pazos
authors.forename: R
authors.initials: R
authors.lastname: Menéndez
authors.forename: C
authors.initials: C
authors.lastname: Alvarez
authors.forename: A
authors.initials: A
authors.lastname: Garateix
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003064:Cnidarian Venoms / Q000302:isolation & purification / Q000494:pharmacology*; D003603:Cytotoxins / Q000302:isolation & purification / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009930:Organic Chemicals / Q000302:isolation & purification / Q000494:pharmacology; D052899:Pore Forming Cytotoxic Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D012615:Sea Anemones / Q000737:chemistry*; D012908:Snails
chemical_list: D003064:Cnidarian Venoms; D003603:Cytotoxins; D009930:Organic Chemicals; D052899:Pore Forming Cytotoxic Proteins; C404794:sticholysin II; C121348:stycholysin I