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

First published online October 27, 2003

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 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 McNeill, B. Articles by Perry, S. F. Search for Related Content PubMed PubMed Citation Articles by McNeill, B. Articles by Perry, S. F.

Catecholamine secretion in trout chromaffin cells experiencing nicotinic receptor desensitization is maintained by non-cholinergic neurotransmission

Brian McNeill, Colin J. Montpetit and Steve F. Perry^*

Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada

View larger version (15K): [in a new window]   Fig. 1. (A) The effects of continuous infusion of control saline (unfilled bars; N=8) or rapidly switching to saline containing nicotine (10–5 mol l–1; filled bars; N=8) or nicotine plus hexamethonium (10–3 mol l–1; cross-hatched bars; N=8) on catecholamine secretion in an in situ perfused posterior cardinal vein preparation of rainbow trout Oncorhynchus mykiss. (B) After 10 min, the preparations were electrically stimulated using a frequency of 20 Hz and maximal catecholamine secretion rates were determined under the various conditions. An asterisk denotes a statistically significant difference from the `pre-switch' (Pre) value; a dagger represents a significant difference from the secretion rate after 10 min; a double dagger represents a significant difference from the control (saline-perfused) group.

View larger version (10K): [in a new window]   Fig. 2. Total catecholamine (adrenaline plus noradrenaline) levels in several tissues that could potentially contribute to catecholamine secretion in the perfused posterior cardinal vein (PCV) preparation; N=6.

View larger version (15K): [in a new window]   Fig. 3. (A) The effects of continuous infusion of control saline (unfilled bars; N=8) or rapidly switching to saline containing nicotine (10–5 mol l–1; filled bars; N=8) or nicotine plus a cocktail of 10–3 mol l–1 hexamethonium and 10–5 mol l–1 atropine (cross-hatched bars; N=8) on catecholamine secretion in an in situ perfused posterior cardinal vein preparation of rainbow trout Oncorhynchus mykiss. (B) After 10 min, the preparations were electrically stimulated using a frequency of 1 Hz and maximal catecholamine secretion rates were determined under the various conditions. An asterisk denotes a statistically significant difference from the `pre-switch' (Pre) value; a dagger represents a significant difference from the secretion rate after 10 min.

View larger version (19K): [in a new window]   Fig. 4. (Ai,Bi) The effects of rapidly switching from control saline to saline containing nicotine (10–5 mol l–1; hatched bars; N=18) or nicotine plus the VPAC receptor antagonist VIP6-28 (10–6 mol l–1; filled bars; N=18) on catecholamine secretion in an in situ perfused posterior cardinal vein preparation of rainbow trout Oncorhynchus mykiss. After 10 min, the preparations were electrically stimulated using a frequency of either (Aii) 20 Hz or (Bii) 1 Hz and maximal catecholamine secretion rates were determined under the various conditions. An asterisk denotes a statistically significant difference from the `pre-switch' (Pre) value; a dagger represents a significant difference from the secretion rate after 10 min; a double dagger represents a significant difference from the control (salineperfused) group.

View larger version (18K): [in a new window]   Fig. 5. The effects of (Aii) cVIP (10–6 mol l–1; N=15), (Bii) Ang II (10–5 mol l–1; N=6) and (Cii) methylcholine (10–3 mol l–1; N=6) on catecholamine secretion rates (Ai–Ci) in posterior cardinal vein preparations previously perfused with control saline (hatched bars) or after rapidly switching to saline containing nicotine (10–5 mol l–1; filled bars). An asterisk denotes a statistically significant difference from the `preswitch' (Pre) value; a dagger represents a significant difference from the secretion rate after 10 min; a double dagger represents a significant difference from the control (saline-perfused) group. Agonist inj. indicates rate measured after agonist injection (see Materials and methods).