Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102-1814, USA.
Neuroscience. 2010 May 5;167(2):216-31. doi: 10.1016/j.neuroscience.2010.02.015. Epub 2010 Feb 12.
Converging evidence suggests that the motivation to seek cocaine during the postpartum period is significantly impacted by the competing incentives of offspring, a stimulus unique to this life stage. In the present study, the functional role of the medial preoptic area (mPOA), a critical site involved in maternal responsiveness, on processing incentive value of pup-associated cues and influencing response allocation for pup- over cocaine-associated environments was investigated using a concurrent pup/cocaine choice conditioned place preference (CPP) paradigm. Early postpartum females with bilateral guide cannulae aimed into the mPOA or into anatomical control sites were conditioned, from postpartum days (PPD) 4 to 7, to associate different uniquely featured environments with pups or cocaine. CPP was tested on PPD8 following intra-mPOA infusions of either 2% bupivacaine or saline vehicle. In two additional experiments, the effects of intra-mPOA infusions of bupivacaine on expression of conditioned responding induced by environments associated with either pups or cocaine were examined separately. Transient inactivation of the mPOA selectively blocked the conditioned preferences for pup-associated environments, significantly contrasting the robust pup-CPP found in non-surgical and intra-mPOA vehicle-treated females. In contrast, mPOA inactivation failed to alter cocaine-CPP in postpartum females. When given a choice between environments associated with pups or cocaine, transient functional inactivation of the mPOA altered choice behavior, biasing the preference of females toward cocaine-associated environments, such that almost all preferred cocaine- and none the pup-associated option. The anatomical specificity was revealed when inactivation of adjacent regions to the mPOA did not affect CPP responses for pups. The findings support a critical role for the mPOA in mediating pup-seeking behavior, and further suggest that the competing properties of pups over alternative incentives, including drugs of abuse, rely on mPOA integrity to provide relevant pup-related information to the circuitry underlying the choice behavior between pups and alternative stimuli.
越来越多的证据表明，产后寻求可卡因的动机受到后代的竞争激励的显著影响，这是这个生命阶段特有的刺激。在本研究中，使用同时进行的幼崽/可卡因选择条件位置偏好（CPP）范式，研究了参与母性行为的关键部位中脑腹侧前脑区（mPOA）对处理与幼崽相关线索的激励价值和影响对幼崽环境的反应分配的功能作用，而不是可卡因相关环境。双侧导向管指向 mPOA 或解剖对照部位的产后第 4 天至第 7 天的雌性被训练与幼崽或可卡因相关的不同独特特征环境相关联。在 mPOA 内注射 2%布比卡因或生理盐水载体后，在产后第 8 天测试 CPP。在另外两个实验中，分别检查了 mPOA 内注射布比卡因对与幼崽或可卡因相关的环境引起的条件反应表达的影响。mPOA 的短暂失活选择性地阻断了对与幼崽相关环境的条件偏好，与非手术和 mPOA 载体处理的雌性中发现的强烈幼崽-CPP 形成鲜明对比。相比之下，mPOA 失活未能改变产后女性的可卡因-CPP。当在与幼崽或可卡因相关的环境之间做出选择时，mPOA 的短暂功能失活改变了选择行为，使女性对可卡因相关环境的偏好偏向，以至于几乎所有女性都更喜欢可卡因，而不喜欢与幼崽相关的选择。当失活相邻区域而不影响与幼崽相关的 CPP 反应时，揭示了解剖学特异性。这些发现支持了 mPOA 在介导幼崽寻求行为中的关键作用，并进一步表明，幼崽对替代激励因素（包括滥用药物）的竞争特性依赖于 mPOA 的完整性，以向在幼崽和替代刺激之间进行选择行为的电路提供相关的幼崽相关信息。
