title: Effects of oxytocin on adreno-medullary catecholamine synthesis, uptake and storage in rats exposed to chronic isolation stress.
abstract: OBJECTIVE
  The adreno-medullar system represents one of the main systems involved in the response to stressful events. The neuropeptide oxytocin, is highly sensitive to the social environment, and regulates autonomic function. Adreno-medullary activity is dependent on the synthesis of catecholamine, its reuptake, release, degradation and vesicular transport. A direct influence of oxytocin on catecholamine synthesizing enzyme and transports in animals exposed to chronic social isolation stress has not been studied yet.
  
  
  METHODS
  In the present study, we examined the effect of chronic oxytocin treatment on the level of plasma catecholamine and its content, mRNA and protein levels of tyrosine hydroxylase (TH), noradrenaline transporter (NET) as well as vesicular monoamine transporter 2 (VMAT2) in the adrenal medulla of socially isolated rats.
  
  
  RESULTS
  Our results show that, by the end of 12 weeks, social isolation did not produce any significant changes in catecholamine content but increased plasma catecholamine level and synthesis in the adrenal medulla. Oxytocin treatment had no further effect either on catecholamine synthesis or content in socially stressed animals whereas a significant elevation of plasma norepinephrine and epinephrine were reduced. On the other hand, chronic isolation caused a significant increase in VMAT2 and decrease in NET protein levels. Oxytocin treatment brought about an increase in protein levels of NET and its return to the levels of control group. Besides, it further increases VMAT2 protein levels in the adrenal medulla of individually housed rats.
  
  
  CONCLUSIONS
  The present results show that peripheral oxytocin treatment enhances catecholamine uptake and storage in the adrenal medulla of chronically isolated animals.
authors.affiliation: a Department of Molecular Biology and Endocrinology , Institute of Nuclear Sciences "Vinca", University of Belgrade , Belgrade , Serbia.
authors.forename: Predrag
authors.initials: P
authors.lastname: Jovanovic
authors.affiliation: a Department of Molecular Biology and Endocrinology , Institute of Nuclear Sciences "Vinca", University of Belgrade , Belgrade , Serbia.
authors.forename: Bojana
authors.initials: B
authors.lastname: Stefanovic
authors.affiliation: a Department of Molecular Biology and Endocrinology , Institute of Nuclear Sciences "Vinca", University of Belgrade , Belgrade , Serbia.
authors.forename: Natasa
authors.initials: N
authors.lastname: Spasojevic
authors.affiliation: b Faculty of Medicine , Institute of Histology and Embryology "Aleksandar Đ. Kostić", University of Belgrade , Višegradska , Belgrade , Serbia.
authors.forename: Nela
authors.initials: N
authors.lastname: Puskas
authors.affiliation: a Department of Molecular Biology and Endocrinology , Institute of Nuclear Sciences "Vinca", University of Belgrade , Belgrade , Serbia.
authors.forename: Sladjana
authors.initials: S
authors.lastname: Dronjak
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D008297:Male; D050484:Norepinephrine Plasma Membrane Transport Proteins / Q000378:metabolism*; D010121:Oxytocin / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012934:Social Isolation; D013315:Stress, Psychological / Q000188:drug therapy / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D050484:Norepinephrine Plasma Membrane Transport Proteins; C493454:Slc18a2 protein, rat; C493226:Slc6a2 protein, rat; D050493:Vesicular Monoamine Transport Proteins; D010121:Oxytocin; D014446:Tyrosine 3-Monooxygenase
keywords: Individual housing; adrenal-medulla; catecholamines; norephinephrine transporter; tyrosine hydroxilase; vesicular monoamine transporter 2