Prefrontal cortex in the rat: Projections to subcortical autonomic, motor, and limbic centers

170

162

The administration of noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonists such as phencyclidine and ketamine has been shown to increase the extracellular concentration of glutamate and serotonin (5-HT) in the medial prefrontal cortex (mPFC). In the present work, we used in vivo microdialysis to examine the effects of the more potent noncompetitive NMDA receptor antagonist, MK-801, on the efflux of glutamate and 5-HT in the mPFC, and whether the MK-801-induced changes in the cortical efflux of both transmitters could be blocked by clozapine and haloperidol given systemically or intra-mPFC. The systemic, but not the local administration of MK-801, induced an increased efflux of 5-HT and glutamate, which suggests that the NMDA receptors responsible for these effects are located outside the mPFC, possibly in GABAergic neurons that tonically inhibit glutamatergic inputs to the mPFC. The MK-801-induced increases of extracellular glutamate and 5-HT were dependent on nerve impulse and the activation of mPFC AMPA/ kainate receptors as they were blocked by tetrodotoxin and NBQX, respectively. Clozapine and haloperidol blocked the MK-801-induced increase in glutamate, whereas only clozapine was able to block the increased efflux of 5-HT. The local effects of clozapine and haloperidol paralleled those observed after systemic administration, which emphasizes the relevance of the mPFC as a site of action of these antipsychotic drugs in offsetting the neurochemical effects of MK-801. The ability of clozapine to block excessive cortical 5-HT efflux elicited by MK-801 might be related to the superior efficacy of this drug in treating negative/cognitive symptoms of schizophrenia.

Section: Discussionmentioning

confidence: 59%

Clozapine and Haloperidol Differently Suppress the MK-801-Increased Glutamatergic and Serotonergic Transmission in the Medial Prefrontal Cortex of the Rat

López-Gil

Babot

Amargós-Bosch

et al. 2007

170

162

“…The layer V pyramidal neurons in ACd integrate widespread inputs from various brain regions (Hoover and Vertes, 2007) and project to multiple subcortical areas, including striatum, amygdala, dorsal raphe, and spinal cord (Gabbott et al, 2005), to facilitate emotional expression, motor coordination, and temporal organization of behavior. In adult mice with early-life stressful experiences and vehicle treatment, mPFC-dependent cognition, including certain aspects of attention (reflected by the percentage of same arm returns) and temporal order memory, was markedly impaired.…”

Section: Discussionmentioning

confidence: 99%

Stress during a Critical Postnatal Period Induces Region-Specific Structural Abnormalities and Dysfunction of the Prefrontal Cortex via CRF1

Yang

Liao

Uribe-Mariño

et al. 2014

During the early postnatal period, environmental influences play a pivotal role in shaping the development of the neocortex, including the prefrontal cortex (PFC) that is crucial for working memory and goal-directed actions. Exposure to stressful experiences during this critical period may disrupt the development of PFC pyramidal neurons and impair the wiring and function of related neural circuits. However, the molecular mechanisms of the impact of early-life stress on PFC development and function are not well understood. In this study, we found that repeated stress exposure during the first postnatal week hampered dendritic development in layers II/III and V pyramidal neurons in the dorsal agranular cingulate cortex (ACd) and prelimbic cortex (PL) of neonatal mice. The deleterious effects of early postnatal stress on structural plasticity persisted to adulthood only in ACd layer V pyramidal neurons. Most importantly, concurrent blockade of corticotropin-releasing factor receptor 1 (CRF 1 ) by systemic antalarmin administration (20 mg/g of body weight) during early-life stress exposure prevented stress-induced apical dendritic retraction and spine loss in ACd layer V neurons and impairments in PFC-dependent cognitive tasks. Moreover, the magnitude of dendritic regression, especially the shrinkage of apical branches, of ACd layer V neurons predicted the degree of cognitive deficits in stressed mice. Our data highlight the region-specific effects of early postnatal stress on the structural plasticity of prefrontal pyramidal neurons, and suggest a critical role of CRF 1 in modulating early-life stress-induced prefrontal abnormalities.

“…Brains were sectioned coronally on a freezing microtome (American Optical Corporation, Buffalo, NY) at 40 mm through the brain and stored in 0.1% NaN 3 in 1 Â phosphate-buffered saline (PBS) at 41C. The adult rat mPFC (Figure 2a), equivalent to the human dorsolateral prefrontal cortex, spans an area of 3 mm 3 bilaterally along the rostral-caudal levels of the rodent brain (Gabbott et al, 2005). Anatomically, the mPFC is clearly distinguished from other cortical areas in bregma regions 4.20-2.70 of the adult rodent brain (Kodama et al, 2004).…”

Section: Immunohistochemistrymentioning

confidence: 99%

Extended Access to Cocaine Self-Administration Produces Long-Lasting Prefrontal Cortex-Dependent Working Memory Impairments

George

Mandyam

Wee

et al. 2007

152

127

Humans with drug addiction exhibit compulsive drug-seeking associated with impairment of prefrontal cortex cognitive function. Whether prefrontal cortex dysfunction is a consequence of chronic drug exposure, or mediates the transition from drug use to drug dependence, is unknown. The current study investigates whether a history of escalated vs controlled cocaine intake is associated with specific working memory impairments, and long-lasting alterations of the dorsomedial prefrontal cortex and orbitofrontal cortex in rats. Working memory was assessed in rats with a history of extended (6 h per session) or limited (1 h per session) access to cocaine (0.5 mg/kg per injection), 3-17 days after the last self-administration session, using a delayed nonmatching-to-sample task. The density of neurons, oligodendrocytes, and astrocytes was quantified in the dorsomedial prefrontal cortex and orbitofrontal prefrontal cortex 2 months after the last self-administration session. Working memory impairments were observed after a history of chronic and escalated cocaine intake, but not after repeated limited access to cocaine. Moreover, working memory impairments were correlated with a decreased density of neurons and oligodendrocytes but not astrocytes in the dorsomedial prefrontal cortex, and with a decreased density of oligodendrocytes in the orbitofrontal cortex. Considering the role of the prefrontal cortex in goal-directed behavior, the prefrontal cortex dysfunctions observed here may exacerbate the loss of control associated with increased drug use and facilitate the progression to drug addiction.