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Effects of substance P on nicotine-induced intracellular Ca2+ dynamics in bovine adrenal chromaffin cells
1999
Suzuki, S. (Hokkaido Univ., Sapporo (Japan)) | Habara, Y. | Kanno, T.
Substance P (SP) is colocalized with ACh in splanchnic nerves that innervate into adrenal medulla and the peptide has been shown to inhibit nicotinic agonists-induced catecholamine secretion. To elucidate the effects of SP on cytosolic Ca(2+) dynamics, the present study was conducted using fura-2-loaded isolated bovine adrenal chromaffin cells. Stimulation of the cells with nicotine (10-100mu-M) produced a rapid rise of cytosolic Ca(2+) concentration ([Ca(2+)]i), the peak level of which increased in a dose-dependent manner, followed by a gradual decay. In the presence of 10mu-M SP, the dose-response relationship of the peak levels shifted downward. Quantitative analyses implied that SP inhibits the nicotine-induced Ca(2+) influx in a noncompetitive manner. Nicotinic acetylcholine receptor is composed of two major functional domains: an agonist-binding site and an ionophore or channel domain. Agonist binding activates ionophore / channel domain and causes mainly Na(+) influx. This Na(+) influx depolarizes the cell and activates voltage-dependent Ca(2+) channels. Based on this fact, the present results indicate that SP dose not block nicotine binding sites but interferes with other sites of nicotinic receptor / channel molecule, most probably a channel domain. It was suggested that SP colocalized with ACh in splanchnic nerves functions as a physiological modulator of catecholamine secretion by non-competitively suppressing ACh-induced cytosolic Ca(2+) dynamics in bovine a
Show more [+] Less [-]Electron microscopy of Cowdria-infected macrophages suggests that in the abscence of binary fission a mosaic of organisms develops from an amorphous electron dense matrix
1999
Du Plessis, J.L. (Agricultural Research Council, Onderstepoort (South Africa). Onderstepoort Veterinary Inst.)
Characterization and observation of animals responsible for rabies post-exposure treatment in Phnom Penh, Cambodia
1999
Reynes, J.M. (Pasteur Institute, Phnom Penh (Cambodia)) | Soares, J.L. | Keo, C. | Ong, S. | Heng, N.Y. | Vanhoye, B.
Cowdria ruminantium DNA is unstable in a SuperCos 1 library
1999
Brayton, K.A. | De Villiers, E.P. | Fehrsen, J. | Nxomani, C. | Collins, N.E. | Allsopp, B.A. (Agricultural Research Council, Onderstepoort (South Africa). Onderstepoort Veterinary Inst.)
Seroprevalence of infectious bursal disease in non-vaccinated indigenous and exotic chickens on selected farms around Gaborone, Botswana
1999
Mushi, E.Z. (Botswana College of Agriculture, Gaborone (Botswana)) | Binta, M.G. | Chabo, R.G. | Ndebele, R.T.
Gastro-intestinal parasites of cattle in the communal grazing system of Botshabelo in the Free State [South Africa]
1999
Dreyer, K. | Fourie, L.J. | Kok, D.J. (Orange Free State Univ., Bloemfontein (South Africa). Dept. of Zoology and Entomology)
Assessment of cattle owners' perceptions and expectations, and identification of constraints on production in a peri-urban, resource-poor environment
1999
Dreyer, K. | Fourie, L.J. | Kok, D.J. (Orange Free State Univ., Bloemfontein (South Africa). Dept. of Zoology and Entomology)
The helminths of ranch calves in the North-eastern mountain grassland of South Africa
1999
Louw, J.P. (Pretoria Univ., Onderstepoort (South Africa). Onderstepoort Veterinary Academic Research Unit)
Evaluation of a proposed odour-baited target to control the tsetse flies Glossina brevipalpis and Glossina austeni (Diptera: Glossinidae) in South Africa
1999
Kappmeier, K. | Nevill, E.M. (Agricultural Research Council, Onderstepoort (South Africa). Onderstepoort Veterinary Inst.)
The production and evaluation of Pasteurella haemolytica leukotoxin in the supernatant of submerged cultures in fermenters
1999
Odendaal, M.W. | Ellis, C.E. (Agricultural Research Council, Onderstepoort (South Africa). Onderstepoort Veterinary Inst.)