Excitability and secretory activity in the salivary gland cells of jawed leeches (Hirudinea: Gnathobdellida).

摘要: Thousands of salivary cells fill the interstices throughout anterior ends jawed leeches. The somata are large (30–200 micron in diameter). They project single processes (ductules) into three jaws, and were found to fire overshooting action potentials 50–85 mV amplitude 100–200 ms duration at low spontaneous rates. not detected presence cobalt (10 mmol l-1), but could be recorded when sodium was absent from Ringer, so they appear calcium-dependent. Salivary material is transported by long these unicellular glands secreted ducts which alternate with paired teeth on jaws. Secretion activated reliably 10(−6) mol l-1 serotonin, other neurotransmitters leech nervous system. Each jaw secretes an average rate 230 nl min-1 secretion completely abolished cobalt. Perfusion serotonin excites gland impulse activity, often evokes bursting. Impulse activity peripherally projecting, serotonergic Retzius both depolarizations cells. In leeches, central neurones control salivation a peripheral release serotonin. This neurotransmitter calcium-dependent calcium, turn, stimulates secretion.