Sexual behaviour in Euplotes raikovi is accompanied by pheromone-induced modifications of ionic currents
Autor(en): | Stock, C Krüppel, T Key, G Lueken, W |
Stichwörter: | Biology; CALCIUM CURRENT; CILIARY ACTIVITY; ciliary reversal; ciliate; DEPOLARIZATION; DIDINIUM; Euplotes raikovi; EXOCYTOSIS; HYPERPOLARIZATION; K+ current; Life Sciences & Biomedicine - Other Topics; membrane potential; NA-CURRENT; PARAMECIUM CELLS; side-stepping reaction; STORES; VANNUS; voltage-dependent Ca2+ current | Erscheinungsdatum: | 1999 | Herausgeber: | COMPANY OF BIOLOGISTS LTD | Journal: | JOURNAL OF EXPERIMENTAL BIOLOGY | Volumen: | 202 | Ausgabe: | 4 | Startseite: | 475 | Seitenende: | 483 | Zusammenfassung: | In the marine ciliate Euplotes raikovi, pheromone released by a complementary mating type (nonself pheromone) induces typical sexual behaviour, whereas self pheromone released by the same mating type generally has no effect. Nonself pheromone evokes a reduction of the mean walking speed by 66 %, a threefold increase in the frequency and duration of long-lasting rest phases and a doubling in the number of side-stepping reactions. Consequently, translocation is strongly reduced and the cells remain in a small area. This could increase the probability of finding a sexual partner for pair formation (conjugation), The usual pattern of rhythmic, spontaneous depolarizations controlling the walking rhythm is absent in nonself-pheromone-stimulated cells. The remaining depolarizations arise from a 4 mV hyperpolarized membrane potential and do not reach the usual amplitudes of 15-20 mV but only of 6-10 mV, In addition, the amplitudes of K+ currents are increased at depolarizations of more than 20 mV by at least 30 %. Hyperpolarization- and depolarization-activated Na+ current amplitudes are increased, whereas the Ca2+ current amplitude remains nearly unaffected. |
ISSN: | 0022-0949 |
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