Central effects of native urotensin II on motor activity, ventilatory movements, and heart rate in the trout Oncorhynchus mykiss.
Urotensin II (UII) has been originally isolated from fish urophysis. However, in fish as in mammals, UII is also produced in brain neurons. Although UII binding sites are widely distributed in the fish central nervous system (CNS), little is known regarding its central activities. In the present study, we have investigated the effects of intracerebroventricular (ICV) administration of synthetic trout UII on the duration of motor activity (ACT; evidenced by bursts of activity on the trace of the ventilatory signal), ventilatory frequency (VF), ventilatory amplitude (VA), and heart rate (HR) in unanesthesized trout, Oncorhynchus mykiss. ICV injection of very low doses of UII (1 and 5 pmol) produced a dose-dependent increase of ACT without affecting VF, VA, or HR. At a higher dose (50 pmol), UII stimulated ACT as well as VF, VA, and HR. ICV injection of trout angiotensin II (5 pmol) did not affect ACT, VF, and VA, but provoked a robust increase in HR. These data provide the first evidence that central administration of UII stimulates motor activity in a nonmammalian vertebrate.
Lancien
Frédéric
F
Laboratoire de Traitement de l'Information Médicale, INSERM U650, EA 2218, Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale, Brest Cedex 3 29238, France.
Leprince
Jérôme
J
Mimassi
Nagi
N
Mabin
Dominique
D
Vaudry
Hubert
H
Le Mével
Jean-Claude
JC
D000704:Analysis of Variance; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000379:methods; D006339:Heart Rate / Q000187:drug effects*; D007276:Injections, Intraventricular / Q000379:methods; D009043:Motor Activity / Q000187:drug effects*; D017686:Oncorhynchus mykiss; D012123:Pulmonary Ventilation / Q000187:drug effects*; D014579:Urotensins / Q000138:chemical synthesis / Q000494:pharmacology*
D014579:Urotensins; D000804:Angiotensin II; C029677:urotensin II