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CELL SIGNALING PATHWAYS ACTIVATED BY NICOTINE

Nicotine is biologically active. It competes with acetylcholine for binding to specific membrane receptors, so-called nicotinic cholinergic receptors (nAChRs). They are widely expressed in the nervous system and skeletal muscle. Nicotinic receptors are also present in many cell types, e.g. epithelial, blood, and cancer cells. When nicotine binds to the nAChRs, the conformation of the receptor subunits changes, opening the receptor channel gate. This allows the influx of sodium and calcium ions into the cell, leading to membrane depolarization.

THE ROLE OF CALCIUM IONS IN ACTIVATION OF THE MAMMALIAN EMBRYO DEVELOPMENT

Fertilization of a mouse oocyte triggers oscillations of the concentration of free calcium ions in ooplasm ([Ca2+] i ). Calcium oscillations are generated in a process involving inositol 1,4,5-triphosphate (IP 3 ) produced by phospholipase C zeta (PLC zeta), a sperm specific isoform of phospholipase C. Calcium transients last for several hours until the time of pronuclei formation. The ability to generate and sustain long-lasting oscillations of [Ca2+] i is developed in oocytes during meiotic maturation, i.e.

The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

Editorial address:
Katedra i Zakład Histologii i Embriologii Uniwersytetu Medycznego w Poznaniu, ul. Święcickiego 6, 60-781 Poznań, tel. +48 61 8546453, fax. +48 61 8546440, email: mnowicki@ump.edu.pl

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