title: Brain as an endocrine source of circulating 5-hydroxytryptamine in ontogenesis in rats.
abstract: This study was aimed to test the authors' hypothesis stating that the developing brain before the closure of the blood brain barrier (BBB) operates as an endocrine organ that secretes classical neurotransmitters and neuropeptides into the general circulation. 5-Hydroxytryptamine (5-HT) was selected as a marker of brain endocrine activity though it is also secreted by peripheral organs. 5-HT was detected in blood of rats in a biologically active concentration at any studied age, from the 21st embryonic day till the 30th postnatal day. The brain was proven to be a source of circulating 5-HT before the BBB closure by showing that the 5-HT concentration in blood decreased significantly after the inhibition of 5-HT synthesis in the brain of neonates. The 5-HT concentration in blood was not diminished after the BBB closure, apparently due to compensatory increase of 5-HT secretion by peripheral sources. Thus, brain-derived 5-HT is delivered to the general circulation before the BBB closure being potentially capable of providing endocrine regulation of target organs.
authors: Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia.
authors: Zubova
authors: Z
authors: Yulia
authors: Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia.
authors: Nasyrova
authors: N
authors: Diana
authors: Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia.
authors: Sapronova
authors: S
authors: Anna
authors: Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia. Electronic address: michael.ugrumov@mail.ru.
authors: Ugrumov
authors: U
authors: Michael
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000196:embryology; D001921:Brain / Q000196:embryology*; D004703:Endocrine System / Q000196:embryology*; D005260:Female; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000096:biosynthesis* / Q000097:blood*
chemical_list: D012701:Serotonin
keywords: 5-Hydroxytryptamine; Blood; Blood brain barrier; Brain; Development; Duodenum