title: Different Ca2+ signalling cascades manifested by mastoparan in the prothoracic glands of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx mori.
abstract: Application of the tetradecapeptide mastoparan to the prothoracic glands (PGs) of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx mori, resulted in increases in intracellular Ca(2+) ([Ca(2+)](i)). In M. sexta, Gi proteins are involved in the mastoparan-stimulated increase in [Ca(2+)](i). However, there is no involvement of Gi proteins in the mastoparan-stimulated increase in [Ca(2+)](i) in prothoracic gland cells from B. mori. Unlike in M. sexta prothoracic glands, in B. mori prothoracic glands mastoparan increases [Ca(2+)](i) even in the absence of extracellular Ca(2+). Pharmacological manipulation of the Ca(2+) signalling cascades in the prothoracic glands of both insect species suggests that in M. sexta prothoracic glands, mastoparan's first site of action is influx of Ca(2+) through plasma membrane Ca(2+) channels while in B. mori prothoracic glands, mastoparan's first site of action is mobilization of Ca(2+) from intracellular stores. In M. sexta, the combined results indicate the presence of mastoparan-sensitive plasma membrane Ca(2+) channels, distinct from those activated by prothoracicotropic hormone or the IP(3) signalling cascade, that coordinate spatial increases in [Ca(2+)](i) in prothoracic gland cells. We propose that in B. mori, mastoparan stimulates Ca(2+) mobilization from ryanodine-sensitive intracellular Ca(2+) stores in prothoracic gland cells.
authors.affiliation: Saxon Academy of Sciences at Leipzig, Department of Neurohormones, Jena, Germany. sd323@cam.ac.uk
authors.forename: Skarlatos G
authors.initials: SG
authors.lastname: Dedos
authors.forename: Dieter
authors.initials: D
authors.lastname: Wicher
authors.forename: Sabine
authors.initials: S
authors.lastname: Kaltofen
authors.forename: Heiner
authors.initials: H
authors.lastname: Birkenbeil
mesh_terms: D000818:Animals; D012831:Bombyx / Q000502:physiology*; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000032:analysis / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005682:Gadolinium / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D018402:Manduca / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology*; D037342:Pertussis Toxin / Q000494:pharmacology; D012433:Ryanodine / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors; D014862:Wasp Venoms / Q000494:pharmacology*
chemical_list: D001896:Boron Compounds; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D013873:Thionucleotides; D014862:Wasp Venoms; D006153:Guanosine Diphosphate; D012433:Ryanodine; D019284:Thapsigargin; C023427:guanosine 5'-O-(2-thiodiphosphate); C037500:mastoparan; D005682:Gadolinium; C109986:2-aminoethoxydiphenyl borate; D037342:Pertussis Toxin; D002118:Calcium