QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online December 22, 2003
Journal of Experimental Biology 207, 411-416 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00778

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kerchove, C. M. Articles by Yamanouye, N. Search for Related Content PubMed PubMed Citation Articles by Kerchove, C. M. Articles by Yamanouye, N. Social Bookmarking                         What's this?

Stimulation of the -adrenoceptor triggers the venom production cycle in the venom gland of Bothrops jararaca

Celine M. Kerchove¹, Sylvia M. Carneiro², Regina P. Markus³ and Norma Yamanouye^1,*

¹ Laboratório de Farmacologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, Brazil
² Laboratório de Biologia Celular, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900, São Paulo, Brazil
³ Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, travessa 14, 05508-900 São Paulo, Brazil

View larger version (14K): [in a new window]   Fig. 1. Dose–response curves for noradrenaline (open squares, N=7) and phenylephrine (filled squares, N=11) in quiescent cells of the venom gland of Bothrops jararaca, as assessed by microphysiometry. Cultured cells were perfused with the agonists for 1 min, a complete dose–reponse curve was constructed in each well, and the interval between successive doses was 30 min. All experiments were done in the presence of the ß-adrenoceptor blocker propranolol. Values are means ± S.E.M.

View larger version (19K): [in a new window]   Fig. 2. Dose–response curves to phenylephrine in secretory cells in different stages of the venom production cycle: quiescent cells (filled squares, N=11), cells collected just after venom extraction (open triangles, N=6), cells collected 4 days (open circles, N=6), 7 days (open diamonds, N=5), 15 days (asterisks, N=6) and 30 days after venom extraction (filled circles, N=6). Note that venom extraction induced receptor downregulation that lasted for at least 15 days. Values are means ± S.E.M.

View larger version (16K): [in a new window]   Fig. 3. In vitro desensitization of the -adrenoceptor in cells of the Bothrops jararaca venom gland. Quiescent cells were incubated for 5 min with 10–4 mol l–1 noradrenaline and kept at 30°C for 24 h(triangles, N=6) before the construction of the dose–response curve to phenylephrine. Control quiescent cells (squares, N=11). Note that incubation with noradrenaline induced receptor downregulation. Values are means ± S.E.M.

View larger version (179K): [in a new window]   Fig. 4. Effect of a single dose of phenylephrine (100 mg kg–1 wet mass, s.c., N=3) on morphology of venom gland cells of reserpine-treated snakes. (A) Venom gland obtained from venom-extracted snakes after treatment with reserpine for 15 days. (B) Venom gland obtained from venom-extracted snakes after treatment with reserpine plus phenylephrine immediately after venom extraction. Note in A the narrow cisterna of the rough endoplasmatic reticulum indicative of lack of venom synthesis and a quiescent Golgi and in B the presence of wide rough endoplasmatic reticulum cisternae and several vesicles in the Golgi complex suggestive of venom production and secretion. G, Golgi apparatus; L, lumen; R, rough endoplasmic reticulum; S, secretory vesicle. Scale bars, 2 µm.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

Twitter