RESUMEN
Cannabinoid receptors and the endocannabinoids anandamide and 2-arachidonoylglycerol have been suggested to regulate food intake in several animal phyla. Orthologs of the mammalian cannabinoid CB(1) and CB(2) receptors have been identified in fish. We investigated the presence of this endocannabinoid system in the brain of the goldfish Carassius auratus and its role in food consumption. CB(1)-like immunoreactivity was distributed throughout the goldfish brain. The prosencephalon showed strong CB(1)-like immunoreactivity in the telencephalon and the inferior lobes of the posterior hypothalamus. Endocannabinoids were detected in all brain regions of C. auratus and an anandamide-hydrolysing enzymatic activity with features similar to those of mammalian fatty acid amide hydrolase was found. Food deprivation for 24 h was accompanied by a significant increase of anandamide, but not 2-arachidonoylglycerol, levels only in the telencephalon. Anandamide caused a dose-dependent effect on food intake within 2 h of intraperitoneal administration to satiated fish and significantly enhanced or reduced food intake at low (1 pg/g body weight) or intermediate (10 pg/g) doses, respectively, the highest dose tested (100 pg/g) being inactive. We suggest that endocannabinoids might variously contribute to adaptive responses to food shortage in fish.
Asunto(s)
Ácidos Araquidónicos/metabolismo , Moduladores de Receptores de Cannabinoides/metabolismo , Ingestión de Alimentos/fisiología , Endocannabinoides , Carpa Dorada/fisiología , Telencéfalo/fisiología , Amidohidrolasas/metabolismo , Secuencia de Aminoácidos , Animales , Ácidos Araquidónicos/farmacología , Moduladores de Receptores de Cannabinoides/farmacología , Ingestión de Alimentos/efectos de los fármacos , Femenino , Hidrocortisona/sangre , Hipotálamo/fisiología , Masculino , Datos de Secuencia Molecular , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Alcamidas Poliinsaturadas , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB1/metabolismoRESUMEN
In this paper, the effects of an estrogenic compound, 4-nonyl-phenol (NP), on the amphibians Rana esculenta and Triturus carnifex are described together with those on sexual differentiation in Xenopus laevis. NP increased plasma vitellogenin in male frogs and newts in a dose-related manner; moreover, inhibitory effects on gonadotropin and prolactin (PRL) secretion by pituitary were found together with an elevation of plasma androgens. NP treatment also caused a remarkable increase in number of prolactin-immunolabeled cells, suggesting that xenoestrogen might induce, at least in the newt pituitary, a PRL accumulation possibly due to a reduction of the hormone release. In addition, both NP and bisphenol A caused feminization by increasing the percentage of female phenotypes in X. laevis, and the in vivo effects were more pronounced than those of estradiol-17beta.