Central effects of trout tachykinins on heart rate variability in trout.
Recent studies in trout have shown that tachykinins might be selectively implicated in important neuroregulatory functions related to the central control of ventilation. In teleost fish, cardiorespiratory coupling probably contributes to heart rate variability (HRV), and the hypoventilatory effects observed after central injection of tachykinins suggest that these peptides also may produce changes in HRV. Consequently, the present study was undertaken to compare the central actions of picomolar doses (25-250 pmol) of trout neuropeptide gamma (NPgamma), substance P (SP), and neurokinin A (NKA) on HRV in unanesthetized rainbow trout. Compared to vehicle-injected trout, Poincaré plot analysis of HRV demonstrated that intracerebroventricular injection of NPgamma dose dependently increased HRV. SP evoked a significant elevation of HRV but only at the highest dose (250 pmol). In contrast, NKA was without any effect on HRV. In conclusion, these results suggest that NPgamma may be selectively implicated in the central control of HRV in trout.
Lancien
Frédéric
F
Université Européenne de Bretagne, Université de Brest, Institut National de la Santé et de la Recherche Médicale (U650), Centre Hospitalier Universitaire de Brest, Brest, France.
Mimassi
Nagi
N
Conlon
John Michael
JM
Le Mével
Jean-Claude
JC
D000818:Animals; D006339:Heart Rate / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D015320:Tachykinins / Q000494:pharmacology*; D014337:Trout / Q000502:physiology*
D010446:Peptide Fragments; D015320:Tachykinins; C059905:tachykinin neuropeptide gamma