Function and modulation of the antennal heart of Periplaneta americana (L.).
The antennal heart of Periplaneta americana, a small accessory circulatory pump in the head, shows a rhythmicity with myogenic automatism. The muscle fibres extending throughout of the dilator muscle are electrically coupled. Among the peptides, proctolin causes a dose-dependent strong excitation, but allatostatin does not affect heart rhythm. However, allatostatin applied before proctolin antagonized the proctolin effect. In contrast to this, an immediate heart block produced by octopamine is similar to that produced by electrical stimulation of the nervus cardioantennalis. This inhibition is caused by a K(+)-dependent hyperpolarization. The second effect of octopamine is a delayed increase of the cAMP level. Because octopamine is present at the antennal heart, a physiological role is assumed.
Institut für Allgemeine Zoologie und Tierphysiologie, Friedrich-Schiller-Universität, Jena, F.R.G.
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Hertel
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Penzlin
D000200:Action Potentials; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D004558:Electric Stimulation; D006321:Heart / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D009479:Neuropeptides / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009655:Octopamine / Q000494:pharmacology / Q000502:physiology; D009842:Oligopeptides / Q000494:pharmacology; D010526:Periplaneta / Q000033:anatomy & histology / Q000502:physiology*; D011188:Potassium / Q000378:metabolism
D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; C076523:allatostatin; D009655:Octopamine; C011536:proctolin; D000242:Cyclic AMP; D011188:Potassium