title: Pineal photoreceptor cells: photoperiodic control of melatonin production after cell dissociation and culture.
abstract: Trout pineal cells were dissociated using a trypsin-DNase digestion technique. An enriched population of photoreceptor cells was selected from a Percoll gradient centrifugation. The ability of cultured photoreceptor cells (selected or not on a Percoll gradient) to produce melatonin rhythmically was investigated during seven 24 h light/dark cycles. During each cycle, trout pineal photoreceptor cells released low amounts of melatonin during daytime and high amounts during night-time. Under continuous darkness, melatonin release was continually high. The profile of its rhythm and that of the activity of the hydroxyindole-O-methyltransferase-the last enzyme of the melatonin biosynthetic pathway-depended on the substrates and on the culture media used. Some of them appear suitable for short- or long-term culture of photoreceptor cells permitting the study of their neuroendocrine properties.
authors.affiliation: Laboratoire de Neurobiologie et Neuroendocrinologie Cellulaires, LIRA CNRS 290, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France. INRA, Station de Physiologie de la Reproduction, 37380 Nouzilly, France and Laboratoire de Neuroendocrinologie, Université de Tours, 37200 Tours, France.
authors.forename: V
authors.initials: V
authors.lastname: Bégay
authors.forename: J
authors.initials: J
authors.lastname: Falcón
authors.forename: C
authors.initials: C
authors.lastname: Thibault
authors.forename: J P
authors.initials: JP
authors.lastname: Ravault
authors.forename: J P
authors.initials: JP
authors.lastname: Collin