Delta Opioid Receptors and Enkephalinergic Signaling within Locus Coeruleus Promote Stress Resilience.

The noradrenergic nucleus locus coeruleus is a key component of the stress circuitry of the brain. During stress, the neuropeptide corticotropin-releasing factor (CRF) is secreted onto LC, increasing LC output and norepinephrine concentration in the brain, which is thought to promote anxiety-like behavior. LC is also innervated by several structures that synthesize and release the endogenous opioid peptide enkephalin onto LC upon stressor termination.

Age- and Sex-Dependent Changes in Locus Coeruleus Physiology and Anxiety-Like Behavior Following Acute Stressor Exposure.

Adolescence is a critical period of development with increased sensitivity toward psychological stressors. Many psychiatric conditions emerge during adolescence and animal studies have shown that that acute stress has long-term effects on hypothalamic-pituitary-adrenal axis function and behavior. We recently demonstrated that acute stress produces long-term electrophysiological changes in locus coeruleus and long-lasting anxiety-like behavior in adolescent male rats.

Anatomically and functionally distinct locus coeruleus efferents mediate opposing effects on anxiety-like behavior.

The locus coeruleus (LC) is a critical node in the stress response, and its activation has been shown to promote hypervigilance and anxiety-like behavior. This noradrenergic nucleus has historically been considered homogeneous with highly divergent neurons that operate en masse to collectively affect central nervous system function and behavioral state. However, in recent years, LC has been identified as a heterogeneous structure whose neurons innervate discrete terminal fields and contribute to distinct aspects of behavior.

Persistent Stress-Induced Neuroplastic Changes in the Locus Coeruleus/Norepinephrine System.

Neural plasticity plays a critical role in mediating short- and long-term brain responses to environmental stimuli. A major effector of plasticity throughout many regions of the brain is stress. Activation of the locus coeruleus (LC) is a critical step in mediating the neuroendocrine and behavioral limbs of the stress response.

Acute Stress Persistently Alters Locus Coeruleus Function and Anxiety-like Behavior in Adolescent Rats.

Stress is a physiological state characterized by altered neuroendocrine signaling, behavioral arousal, and anxiety. Chronic or traumatic stress may predispose individuals for multiple somatic and psychiatric illnesses. The locus coeruleus (LC) is a major node in the stress response that integrates input from multiple stress responsive neural circuits and releases norepinephrine (NE) throughout the central nervous system (CNS) to promote vigilance and anxiety.

Noradrenergic Modulation of Cognition in Health and Disease.

Norepinephrine released by the locus coeruleus modulates cellular processes and synaptic transmission in the central nervous system through its actions at a number of pre- and postsynaptic receptors. This transmitter system facilitates sensory signal detection and promotes waking and arousal, processes which are necessary for navigating a complex and dynamic sensory environment. In addition to its effects on sensory processing and waking behavior, norepinephrine is now recognized as a contributor to various aspects of cognition, including attention, behavioral flexibility, working memory, and long-term mnemonic processes.