Hypothalamic noradrenaline synthesis, uptake and storage in rats during adaptation to long-term individual housing

Abstract

The brain monoamine systems play a crucial role in mediating social behaviors. In order to assess the effect of socially isolated rats on neurochemical substrates in hypothalamus we measured levels of tyrosine hydroxylase (TH), noradrenaline transporter (NET) and vesicular monoamine transporter 2 (VMAT 2). Our results show that 12 weeks of social isolation produced no significant changes in noradrenaline content in hypothalamus. The levels of TH and NET were elevated in these animals, whereas level of VMAT 2 was unchanged. The data suggests that both enhanced synthesis and reuptake may aid in the recovery of noradrenaline content in the hypothalamus. The adaptation of the hypothalamic noradrenaline to long period of stress may have great physiological importance and may represent mechanism designed to help the organism adapt to the deleterious effects of chronic indiviual housing.