Serotonin as a regulator of hypothalamic-pituitary-interrenal activity in teleost fish.
Evidence for the presence of a serotonin1A (5-HT1A) receptor subtype in the salmonid fish brain has recently been presented. In the present study the potent 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) was tested for its effect on plasma cortisol concentrations in rainbow trout (Oncorhynchus mykiss). Blood was sampled and 8-OH-DPAT administered through a catheter in the dorsal aorta. Thirty minutes after the injection of 40 microg of 8-OH-DPAT/kg, plasma cortisol levels had increased from 12 to 149 ng/ml, whereupon they fell, reaching baseline levels after 4 h. The effect of 1-40 microg 8-OH-DPAT/kg on plasma cortisol concentrations was dose-dependent. The results lends further support to the hypothesis that the brain serotonergic system plays a key role in integrating autonomic, behavioral and neuroendocrine stress-responses in fish as well as mammals, suggesting that not only the structural and biochemical organization, but also the function of the serotonergic system has been conserved during vertebrate evolution.
Winberg
S
S
Department of Animal Development and Genetics, Uppsala University, Sweden. svante.winberg@devbiol.uu.se
Nilsson
A
A
Hylland
P
P
Söderstöm
V
V
Nilsson
G E
GE
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007269:Injections, Intra-Arterial; D007700:Kinetics; D017686:Oncorhynchus mykiss; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology*; D011985:Receptors, Serotonin / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1
D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D006854:Hydrocortisone