Profiles of secreted neuropeptides and catecholamines illustrate similarities and differences in response to stimulation by distinct secretagogues.
Level 5 - mechanism / opinion, no new human data
Bench/in vitro cell culture study
PubMed 26092702 · doi:10.1016/j.mcn.2015.06.008
What was done
Researchers evaluated the secretion profiles of neuropeptides (Met-enkephalin, galanin, NPY, VIP) and catecholamines (dopamine, norepinephrine, epinephrine) from sympathoadrenal chromaffin cells. Cells were stimulated with six distinct secretagogues: potassium chloride (KCl) depolarization, nicotine, carbachol, pituitary adenylate cyclase-activating polypeptide (PACAP), bradykinin, and histamine.
What was found
All six secretagogues stimulated the co-release of the measured neuropeptides and catecholamines. The general rank-orders of secreted transmitters were similar across secretagogues, though differences occurred in the secreted amounts of each transmitter. Epinephrine showed the highest secretion levels among catecholamines, and Met-enkephalin showed the highest secretion levels among neuropeptides. Secreted catecholamine levels were greater overall than neuropeptide levels. No specific numbers, concentrations, or statistical significance values were reported in the abstract.
Why it matters
This study shows how sympathoadrenal chromaffin cells coordinate the differential co-release of neuropeptide and catecholamine cocktails depending on the stimulating secretagogue.
Limits
This is an in vitro study and the abstract does not state the species source of the chromaffin cells, the sample size (n), or any quantitative concentrations and error ranges. Findings in isolated cell cultures cannot be directly equated to in vivo sympathoadrenal responses.
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