Nicniocaill Brid, Gratton Alain
Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 LaSalle Blvd, Montréal (Verdun), H4H 1R3, Québec, Canada.
Psychopharmacology (Berl). 2007 Apr;191(3):835-42. doi: 10.1007/s00213-007-0723-1. Epub 2007 Feb 9.
The medial prefrontal cortex (PFC) receives stress-sensitive dopamine (DA) and noradrenergic (NE) projections from the ventral tegmental area and locus coeruleus, respectively, and evidence from various sources point to a complex functional interaction between these two systems. Stress will also stimulate DA transmission in the nucleus accumbens (NAcc), and our previous work has shown that this response is under the indirect inhibitory control of a DA-sensitive mechanism in PFC.
We examined the possibility that the NAcc DA stress response is also modulated by prefrontal cortical NE.
We used voltammetry to study in freely behaving rats the effects of local applications of alpha(1) (benoxathian 0.1, 1, 10 nmol), alpha(2) (SKF86466), and beta(1/2) (alprenolol) receptor selective antagonists into the PFC on the NAcc DA response to tail-pinch stress.
The NAcc DA stress response was dose-dependently inhibited by local PFC blockade of alpha(1) receptors. Additional tests revealed, however, that the DA stress response in NAcc is unaffected after local alpha(1) receptor activation with cirazoline. Furthermore, at equivalent doses, neither alpha(2) nor beta(1/2) receptor blockade significantly affected the NAcc DA stress response.
These data indicate that stress-induced activation of subcortical DA transmission is modulated by the NE input to PFC acting at alpha(1) receptors. They suggest that, under normal circumstances, this system exerts a facilitatory or enabling influence on the NAcc DA stress response.
内侧前额叶皮质（PFC）分别从腹侧被盖区和蓝斑接收对压力敏感的多巴胺（DA）和去甲肾上腺素能（NE）投射，并且来自各种来源的证据表明这两个系统之间存在复杂的功能相互作用。应激也会刺激伏隔核（NAcc）中的DA传递，并且我们之前的研究表明这种反应受PFC中DA敏感机制的间接抑制控制。
我们研究了前额叶皮质NE也调节NAcc DA应激反应的可能性。
我们使用伏安法在自由活动的大鼠中研究向PFC局部应用α(1)（苯恶噻嗪0.1、1、10 nmol）、α(2)（SKF86466）和β(1/2)（阿普洛尔）受体选择性拮抗剂对NAcc DA对夹尾应激反应的影响。
局部PFC阻断α(1)受体可剂量依赖性地抑制NAcc DA应激反应。然而，进一步的测试表明，用西拉唑啉局部激活α(1)受体后，NAcc中的DA应激反应不受影响。此外，在等效剂量下，α(2)或β(1/2)受体阻断均未显著影响NAcc DA应激反应。
这些数据表明，应激诱导的皮质下DA传递激活受作用于α(1)受体的PFC的NE输入调节。它们表明，在正常情况下，该系统对NAcc DA应激反应发挥促进或增强作用。
