Effect of the pineal gland and melatonin on dopamine release from perifused hypothalamus of mature female carp during spawning and winter regression

• Published in: Acta ichthyologica et piscatoria Vol. 35; no. 2; pp. 65 - 71
• Main Authors: Popek, W. (Krakow Agricultural University (Poland). Dept. of Ichthyobiology and Fisheries), Luszczek-Trojnar, E. (Krakow Agricultural University (Poland). Dept. of Animal Physiology), E-mail: etrojnar@wp.pl, Drag-Kozak, E, Fortuna-Wronska, D, Epler, P. (Krakow Agricultural University (Poland). Dept. of Ichthyobiology and Fisheries)
• Format: Journal Article
• Language: English
• Published: Pensoft Publishers 2005
• Subjects: Brain; car; Carp; Carpa; Carpe; Cerebro; Control hormonal; Contrôle hormonal; Cyprinus carpio; Dopamina; Dopamine; Encéphale; Estímulo; Females; Femelle; Freshwater; Glándula pineal; Hembra; Hivernage; Hormonal control; Invernación; Melatonin; Melatonina; Mélatonine; Oviposición; Oviposition; perifusion; Pineal body; pineal gland; Ponte; Secreción; Secretion; Stimuli; Stimulus; Sécrétion; Wintering; Épiphyse
• ISSN: 0137-1592; 1734-1515
• DOI: 10.3750/aip2005.35.2.01

Melatonin regulates various physiological and neuroendocrinological processes, and may have an indirect influence on animal reproduction through dopaminergic structures of the hypothalamus, but the mechanism involved remains unknown, also in fish, for this reason, the present experiment was conducted. The effect of melatonin on dopamine release from hypothalamic cells of mature female carp in vitro was determined. Hypothalami were perifused with a mineral medium containing melatonin (group 1), in the presence of implanted pineal glands (group 2), and with a pure mineral medium (control). Perifusion was 180 min long and samples of the effluent perifusate were collected at 15-minute intervals. Dopamine concentration in the medium was analysed radioenzymatically. The experiment was carried out in the summer during spawning and in the winter during regression. The results indicate that melatonin inhibits the release of dopamine from hypothalamic cells. This effect was only noticeable in the experiment conducted during the spawning period. The present findings show that melatonin may have a role in the hypothalamic control of hypophyseal activity during the spawning period of carp