Puslapis 1 nuo 133 rezultatus
Nicotine reduces the amplitude of the fertilization potential in sea urchin eggs, at least in part because it decreases the slope of the current voltage relation of the unfertilized egg membrane. The reduced fertilization potential amplitude provides an electrophysiological explanation for previous
Agonists of nicotinic cholinoreceptors (n-AChR) and 1-acetyl-4-methylpiperazine (100 microM) had no effect on early embryogenesis in sea urchins, while in the presence of phorbol-12-myristate-13-acetate (PMA) and various other protein kinase C activators, these agents induced rapid lysis of oocytes
The number of sperm incorporated into eggs made polyspermic with varying concentrations of nicotine (0.025-0.25%, v/v) appears to be directly related to the concentrations employed. The cortical response is morphologically equivalent to that observed in control preparations. Shortly after their
Smokeless tobacco use is on the upswing in some parts of the world, including parts of SEAR. It is therefore important to monitor this problem and understand the possible consequences on public health. Material for this review was obtained from documents and data of the World Health Organization,
Agonists of nicotinic acetylcholine receptors (nAChR) nicotine and 1-acetyl-4-methylpiperazine do not act on the early sea urchin embryogenesis but evoke calcium shock in both oocytes and early embryos under certain conditions. Many nAChR ligands protect both oocytes and embryos against this shock.
Sea urchin embryos and larvae provide an inexpensive high-throughput system for determining developmental actions of neuropharmacologic agents or environmental neurotoxins in both applied and basic biologic contexts. The use of this system for the testing of chlorpyrifos, 1-nicotine, lipophilic
: While alkaloids often exert unique pharmacological effects on animal cells, exposure of sea urchin eggs to nicotine causes polyspermy at fertilization in a dose-dependent manner. Here, we studied molecular mechanisms underlying the phenomenon. Although nicotine is an agonist of ionotropic
Choline esters of polyenoic fatty acids block cleavage divisions of sea urchins and evoke the formation of one-cell multinuclear embryos. If the fatty acids AA-Ch or DHA-Ch are added at the mid or late blastula stage, many cells are extruded, forming extra-embryonic cell clusters near the animal
We reported previously that blood levels of nicotine in suicidal smokers tend to be significantly higher than those in non-suicidal smokers, and blood level of nicotine seems to be a useful criterion for discriminating suicide from other types of death. In this paper, we report nicotine and cotinine
Before white man brought his alcohol to the South Pacific, the indigenes were using many wild plants possessing psychoactive properties. The most prominent were betel in much of Melanesia, kava in much of Polynesia, and pituri in much of Australia. The use of each of these three drugs was