All Topics  
Locus ceruleus

 

 
   Email Print
   Bookmark   Link
 

 

Locus ceruleus
 
 
  Topics Locus ceruleus Topic Home

The Locus coeruleus, also spelled locus caeruleus, is a nucleus in the brain stem
Brain stem

The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves....
 involved with physiological
Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
 responses to stress
Stress (medicine)

Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or body threats to the organism, whether actual or imagined....
 and panic
Panic

Panic is a sudden fear which dominates or replaces thinking and often affects groups of people or animals. Panics typically occur in disaster situations, or violent situations which may endanger the overall health of the affected group....
. It was discovered in the 1700s by Félix Vicq-d'Azyr
Félix Vicq-d'Azyr

F?lix Vicq d'Azyr was a French physician and anatomist, the originator of comparative anatomy and discoverer of the theory of homology in biology....
.

Its name is derived from the Latin words "caeruleus" and "locus" meaning, literally, "the blue spot" due to its somewhat azure appearance in unstained brain tissue. Caeruleus is the classical Latin spelling, but coeruleus, a more archaic form, is the more common spelling.






Discussion
Ask a question about 'Locus ceruleus'
Start a new discussion about 'Locus ceruleus'
Answer questions from other users
Full Discussion Forum



Encyclopedia


The Locus coeruleus, also spelled locus caeruleus, is a nucleus in the brain stem
Brain stem

The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves....
 involved with physiological
Physiology

Physiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided between plant physiology and animal and all living things physiology but the principles of physiology are universal, no matter what particular organism is being studied....
 responses to stress
Stress (medicine)

Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or body threats to the organism, whether actual or imagined....
 and panic
Panic

Panic is a sudden fear which dominates or replaces thinking and often affects groups of people or animals. Panics typically occur in disaster situations, or violent situations which may endanger the overall health of the affected group....
. It was discovered in the 1700s by Félix Vicq-d'Azyr
Félix Vicq-d'Azyr

F?lix Vicq d'Azyr was a French physician and anatomist, the originator of comparative anatomy and discoverer of the theory of homology in biology....
.

Its name is derived from the Latin words "caeruleus" and "locus" meaning, literally, "the blue spot" due to its somewhat azure appearance in unstained brain tissue. Caeruleus is the classical Latin spelling, but coeruleus, a more archaic form, is the more common spelling. The spelling ceruleus, formed by contraction of the diphthongs ae or oe into e, is an American English
American and British English spelling differences

American and British English spelling differences are one aspect of American and British English differences.The spelling systems of Commonwealth of Nations countries, for the most part, closely resemble the British system....
 form.

Anatomy

The locus coeruleus (or "LC") is located within the dorsal wall of the rostral pons
Pons

The pons is a structure located on the brain stem. It is cranial to the medulla oblongata, caudal to the midbrain, and ventral to the cerebellum....
 in the lateral floor of the fourth ventricle
Fourth ventricle

The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle....
. This nucleus is the principal site for synthesis of norepinephrine
Norepinephrine

Norepinephrine or noradrenaline is a catecholamine with dual roles as a hormone and a neurotransmitter.As a stress hormone, norepinephrine affects parts of the brain where attention and responding actions are controlled....
 in the brain, and is composed of mostly medium-size neurons. Melanin
Melanin

Melanin is a class of compounds found in the plant, animal, and protista kingdom , where it serves predominantly as a pigment. The class of pigments are derivatives of the amino acid tyrosine....
 granules inside the LC contribute to its blue color; it is thereby also known as the nucleus pigmentosus pontis, meaning "heavily pigmented nucleus of the pons." The neuromelanin is formed by the polymerization
Polymerization

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains....
 of norepinephrine and is analogous to the black dopamine
Dopamine

Dopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the human brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors ? D1, D2, D3, D4 and D5, and their variants....
-based neuromelanin in the substantia nigra
Substantia nigra

The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in dopaminergic neurons....
.

Connections

The projections of this nucleus reach far and wide, innervating the spinal cord, the brain stem, cerebellum
Cerebellum

The cerebellum is a region of the brain that plays an important role in the integration of perception, coordination and motoneuron control. In order to coordinate motor control, there are many neural pathways linking the cerebellum with the cerebrum motor cortex and the spinocerebellar tract ....
, hypothalamus, the thalamic relay nuclei, the amygdala, the basal telencephalon, and the cortex. The norepinephrine from the LC has an excitatory effect on most of the brain, mediating arousal and priming the brain’s neurons to be activated by stimuli. It has been said that a single noradrenergic neuron can innervate the entire cerebral cortex via its branches.

As an important homeostatic
Homeostasis

Homeostasis is the property of a system, either open system or closed system, that regulates its internal environment and tends to maintain a stable, constant condition....
 control center of the body, the locus coeruleus receives afferents from the hypothalamus
Hypothalamus

The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland ....
. The cingulate gyrus
Cingulate gyrus

Cingulate gyrus is a gyrus in the medial part of the brain. It partially wraps around the corpus callosum and is limited above by the cingulate sulcus....
 and the amygdala
Amygdala

The are almond-shaped groups of neurons located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotions, the amygdalae are considered part of the limbic system....
 also innervate the LC, allowing emotional pain and stressors to trigger noradrenergic responses. The cerebellum and afferents from the raphe nuclei
Raphe nuclei

The raphe nuclei are a moderate-size cluster of nucleus found in the brain stem. Their main function is to release serotonin to the rest of the brain....
 also project to the LC, particularly the raphe pontis and raphe dorsalis.

The locus coeruleus receives inputs from a number of other brain regions, primarily:
  • Medial
    Medial

    In abstract algebra, a medial Magma_ is a set with a binary operation which satisfies the identity , or more simply, using the convention that juxtaposition has higher precedence....
     prefrontal cortex
    Prefrontal cortex

    The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the primary motor cortex and premotor cortex areas....
    , whose connection is constant, excitatory, and increases in strength with raised activity levels in the subject
  • Nucleus paragigantocellularis, which integrates autonomic
    Autonomic

    Autonomic can refer to several things, including:*Autonomic nervous system*Autonomic computing*Autonomic system *Autonomic networking...
     and environment
    Natural environment

    The natural environment, commonly referred to simply as the environment, is a term that encompasses all life and non-living things occurring nature on Earth or some region thereof....
    al stimuli
  • Nucleus prepositus hypoglossi
    Nucleus prepositus hypoglossi

    Located in the medulla, the nucleus prepositus hypoglossi or NPH is part of the horizontal gaze holding system. It functions as a neural integrator....
    , which is involved in gaze
  • Lateral hypothalamus
    Hypothalamus

    The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland ....
    , which releases orexin
    Orexin

    Orexins, also called hypocretins, are the common names given to a pair of highly excitatory neuropeptide hormones that were simultaneously discovered by two groups of researchers in rat brains....
    , which, as well as its other functions, is excitatory in the locus coeruleus.


Function

The locus coeruleus is studied in relation to clinical depression
Clinical depression

Major depressive disorder is a mental disorder characterized by a pervasive depression , low self-esteem, and anhedonia in normally enjoyable activities....
, panic disorder
Panic disorder

Panic Disorder is an anxiety disorder characterized by recurring severe panic attacks. It may also include significant behavioral change lasting at least a month and of ongoing worry about the implications or concern about having other attacks....
, and anxiety
Anxiety

Anxiety is a psychological and physiological state characterized by cognitive, somatic, emotional, and behavioral components. These components combine to create an unpleasant feeling that is typically associated with uneasiness, fear, or worry....
. Some antidepressant medications including reboxetine
Reboxetine

Reboxetine is an antidepressant drug used in the treatment of clinical depression, panic disorder and ADHD, developed by Pharmacia . Its mesylate salt is sold under tradenames including Edronax, Norebox, Prolift, Solvex, Davedax or Vestra....
, venlafaxine
Venlafaxine

Venlafaxine is an antidepressant of the serotonin-norepinephrine reuptake inhibitor class first introduced by Wyeth in 1993. It is prescribed for the treatment of major depressive disorder and anxiety disorders, among other uses....
, and bupropion
Bupropion

Bupropion is an atypical antidepressant that acts as a norepinephrine reuptake inhibitor and dopamine reuptake inhibitor, and nicotinic antagonist....
, as well as ADHD medication atomoxetine
Atomoxetine

Atomoxetine is a non-stimulant drug approved for the treatment of attention-deficit hyperactivity disorder . It is sold in the form of the hydrochloride salt of atomoxetine, a norepinephrine reuptake inhibitor....
, are believed to act on neuron
Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
s in this area. This area of the brain is also intimately involved in REM sleep.

Psychiatric research has documented that enhanced noradrenergic postsynaptic responsiveness in the neuronal pathway (brain circuit) that originates in the locus coeruleus and end in the basolateral nucleus of the amygdala
Amygdala

The are almond-shaped groups of neurons located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotions, the amygdalae are considered part of the limbic system....
 is a major factor in the pathophysiology of most stress
Stress (medicine)

Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or body threats to the organism, whether actual or imagined....
-induced fear-circuitry disorders and especially in posttraumatic stress disorder (PTSD). The LC neurons are probably the origin of the first or second “leg” of what has been recently termed the "PTSD candidate circuit." Combat-related PTSD (in a 2005 study of deceased American army veterans from World War II) was shown to be associated with a postmortem diminished number of neurons in the locus coeruleus (LC) on the right side of the brain. The role of the LC in PTSD may explain the dramatic effectiveness of two generic medications, propranolol
Propranolol

Propranolol is a non-selective beta blocker mainly used in the treatment of hypertension. It was the first successful beta blocker developed. It is the only drug proven effective for the prophylaxis of migraines in children....
 and prazosin
Prazosin

Prazosin, trade names Minipress,Vasoflex and Hypovase, is a sympatholytic drug used to treat high blood pressure . It belongs to the class of alpha-adrenergic blockers, which lower blood pressure by relaxing blood vessels....
 for the secondary prevention and treatment of PTSD, respectively.

In stress

The locus coeruleus is responsible for mediating many of the sympathetic effects during stress
Stress (medicine)

Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or body threats to the organism, whether actual or imagined....
. The locus coeruleus is activated by stress, and will respond by increasing norepinephrine
Norepinephrine

Norepinephrine or noradrenaline is a catecholamine with dual roles as a hormone and a neurotransmitter.As a stress hormone, norepinephrine affects parts of the brain where attention and responding actions are controlled....
 secretion, which in turn will increase cognitive function (through the prefrontal cortex
Prefrontal cortex

The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the primary motor cortex and premotor cortex areas....
), increase motivation (through nucleus accumbens
Nucleus accumbens

The nucleus accumbens , also known as the accumbens nucleus or as the nucleus accumbens septi , is a collection of neurons within the forebrain....
), activate the hypothalamic-pituitary-adrenal axis
Hypothalamic-pituitary-adrenal axis

The hypothalamic-pituitary-adrenal axis , also known as thelimbic-hypothalamic-pituitary-adrenal axis , is a complex set of direct influences and feedback interactions among the hypothalamus , the pituitary gland , and the adrenal glands ....
, and increase the sympathetic discharge/inhibit parasympathetic tone (through the brainstem). Specific to the activation of the hypothalamo-pituitary adrenal axis, norepinephrine will stimulate the secretion of corticotropin-releasing factor from the hypothalamus
Hypothalamus

The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland ....
, which induces adrenocorticotropic hormone
Adrenocorticotropic hormone

Adrenocorticotropic hormone is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress ....
 release from the anterior pituitary
Anterior pituitary

The anterior pituitary comprises the Anterior#Usage in human anatomy lobe of the pituitary gland and is part of the endocrine system. Unlike the posterior pituitary, the anterior lobe is genuinely glandular, hence the root adeno in its name....
 and subsequent cortisol synthesis in the adrenal glands. Norepinephrine released from locus coeruleus will feedback to inhibit its production, and corticotropin-releasing hormone will feedback to inhibit its production, while positively feeding to the locus coeruleus to increase norepinephrine production.

In opiate withdrawal

Opioids inhibit the firing of neurons in the locus coeruleus. When opioid consumption is stopped, the increased activity of the locus coeruleus contributes to the symptoms of opiate withdrawal. The alpha2 adrenoceptor agonist clonidine is used to counteract this withdrawal effect by decreasing adrenergic neurotransmission from the locus coeruleus.

See also

  • Raphe nucleus
  • Substantia nigra
    Substantia nigra

    The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in dopaminergic neurons....
  • Reticular formation
    Reticular formation

    The reticular formation is a part of the brain that is involved in actions such as awaking/sleep cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli....


External links

  • at East Tennessee State University
    East Tennessee State University

    East Tennessee State University is an accredited United States university, founded October 2, 1911 and located in Johnson City, Tennessee, Tennessee....
  • at University of Texas at Austin
    University of Texas at Austin

    The University of Texas at Austin is a public university research university located in Austin, Texas, Texas, United States, and is the flagship#University campuses institution of University of Texas System....
  • at University of Virginia
    University of Virginia

    The University of Virginia is a public university research university located in Charlottesville, Virginia, founded by Thomas Jefferson. Conceived by 1800 and established in 1819, it is the only university in the United States to be designated a World Heritage Site by UNESCO, an honor it shares with nearby Monticello....