Effects of serotonin and serotonin antagonists on chick embryogenesis

Abstract

Serotonin and some selected substances known to interfere with its formation (diethyldithiocarbamate) and function (Catron, 5-methyltryptamine, promethazine) were tested for their ability to affect chick embryo morphogenesis during the first 48 h of development. To detect possible differences in sensitivity between the successive morphogenetic events taking place during this period, the treatment was begun at successively more advanced stages corresponding to embryo ages of between 4 and 30 h incubation. In all cases, the treatment was terminated at an embryo age of 48 h incubation. The treatment was performed both in ovo and in vitro.With some exceptions, the substances induced malformations of the same characteristic types. The developmental processes subjected to disturbances included blastoderm expansion, primitive streak formation, neurulation with brain formation, and somitogenesis. At the cellular level, the malformations can be traced to delayed yolk degradation, impaired formation and function of microvilli, and impaired ability of the embryo cells to change shape.All of the tested chemicals can be expected to interfere with intracellular levels of serotonin. They obviously interfered with decomposition of the yolk granules, recognized centres for intracellular serotonin formation and we therefore conclude that the observed morphogenetical disturbances are ultimately due to impairment of the endogenous serotonin formation. We suggest that, in morphogenesis, serotonin primarily promotes the activity of microtubules and microfilaments.

Reduction of intraspecific aggression in adult rats by neonatal treatment with a selective serotonin reuptake inhibitor

“…These effects may be related to an alteration of the serotoninergic system occurring during development, as suggested by Palén et al (8). In a study on chicken embryos, these authors observed that drugs acting on serotonin synthesis and release, or on the activation of serotoninergic receptors may cause disturbances of growth and development in several tissues, including the nervous system, during embryogenesis.…”

“…Furthermore, experimental evidence indicates that serotonin can influence embryogenesis and growth (7,8) presumably by acting as a developmental signal (9) or a neurotrophic factor (10). A role of serotonin in regulating the development of serotonin neurons themselves has also been demonstrated (7).…”

Neonatal treatment with fluoxetine reduces depressive behavior induced by forced swim in adult rats

“…In addition, the BDNF plays an important role in development, synapse remodeling 11 and it has trophic effects on serotonergic neurons in the central nervous system 12 . Furthermore, experimental works indicates that itself 5-HT can influence the embryogenesis and the growth 13,14 presumably by acting as a developmental sign 15 or as a neurotrophic factor 16,17 . Moreover, it is well known that very fast growth and development of the nervous system occur during pregnancy and suckling, and that pharmacological or nutritional manipulations at this phase, can induce drastic morphological and functional changes in these processes 15,18,19 .…”

Neonatal exposure to citalopram, a serotonin selective reuptake inhibitor, programs a delay in the reflex ontogeny in rats

“…In this phenomenon, an environmental alteration during a critical developmental period would have persistent effects on the structure and function of the body 5,6 . experimental evidence indicates that serotonin can also influence embryogenesis and growth 7,8 by acting, presumably, as a developmental signal 9 or as a neurotrophic factor 10 . Furthermore, serotonin seems to play a role in regulating the development of the mammalian brain through actions on the serotoninergic neurons themselves 8,11,12 .…”