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Communication networks in the brain: neurons, receptors, neurotransmitters, and alcohol.

Lovinger DM - Alcohol Res Health (2008)

Bottom Line: Hundreds of molecules are known to act as neurotransmitters in the brain.Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones.It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Integrative Neuroscience at the National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland.

ABSTRACT
Nerve cells (i.e., neurons) communicate via a combination of electrical and chemical signals. Within the neuron, electrical signals driven by charged particles allow rapid conduction from one end of the cell to the other. Communication between neurons occurs at tiny gaps called synapses, where specialized parts of the two cells (i.e., the presynaptic and postsynaptic neurons) come within nanometers of one another to allow for chemical transmission. The presynaptic neuron releases a chemical (i.e., a neurotransmitter) that is received by the postsynaptic neuron's specialized proteins called neurotransmitter receptors. The neurotransmitter molecules bind to the receptor proteins and alter postsynaptic neuronal function. Two types of neurotransmitter receptors exist-ligand-gated ion channels, which permit rapid ion flow directly across the outer cell membrane, and G-protein-coupled receptors, which set into motion chemical signaling events within the cell. Hundreds of molecules are known to act as neurotransmitters in the brain. Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones. This article reviews the chemical nature, neuronal actions, receptor subtypes, and therapeutic roles of several transmitters, neurotrophins, and hormones. It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction.

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Related in: MedlinePlus

Schematic drawing of the γ-aminobutyric acid receptor (GABAA) ligand-gated ion channel complex. The receptor molecule is formed by the confluence of five subunit proteins. In this case, two of the subunits are of the α type, two β and one γ, although many combinations of the 20 known subunits are possible. Globular regions of the protein stick out from the membrane on the extracellular side, and the interfaces between these regions are targets for GABA and for the benzodiazepines and related drugs. The protein domains that span the outer cell membrane are depicted as cylinders. These regions are thought to be targets for general anesthetics (e.g., propofol) neurosteroids, and alcohol. A hole in the middle of the five subunits is the ion conduction pathway, or channel pore.
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f4-arh-31-3-196: Schematic drawing of the γ-aminobutyric acid receptor (GABAA) ligand-gated ion channel complex. The receptor molecule is formed by the confluence of five subunit proteins. In this case, two of the subunits are of the α type, two β and one γ, although many combinations of the 20 known subunits are possible. Globular regions of the protein stick out from the membrane on the extracellular side, and the interfaces between these regions are targets for GABA and for the benzodiazepines and related drugs. The protein domains that span the outer cell membrane are depicted as cylinders. These regions are thought to be targets for general anesthetics (e.g., propofol) neurosteroids, and alcohol. A hole in the middle of the five subunits is the ion conduction pathway, or channel pore.

Mentions: Steroid hormones––small, complex molecules involved in intercellular communication—are highly lipid soluble and have a variety of actions in the body and brain. For example, corticosteroids are released from the cortex of the adrenal glands located on top of the kidneys in response to external stress and are carried by the bloodstream to their sites of action throughout the body and brain (Brunton et al. 2005). It now is widely appreciated that steroids have two mechanisms of action. The traditional steroid signaling pathway involves an intracellular steroid receptor that resides in the cytosol when unbound and translocates to the cell nucleus when it is bound with the steroid (Brunton et al. 2005; Hayashi et al. 2004) (see figure 3C). The receptor protein then can bind to DNA and directly influence the transcription of a variety of genes. The second type of steroid hormone signaling involves actions on cell surface receptors. For example, derivatives of the sex steroid progesterone interact with the A-type receptors for the neurotransmitter γ-aminobutyric acid (GABA) (i.e., GABAA receptors) to enhance receptor function allosterically by producing a conformation, or shape, change in the receptor (Mitchell et al. 2008) (see figure 4). The so-called neurosteroids that act within the brain can be generated locally within CNS tissue and thus can have paracrine2 as well as endocrine actions.


Communication networks in the brain: neurons, receptors, neurotransmitters, and alcohol.

Lovinger DM - Alcohol Res Health (2008)

Schematic drawing of the γ-aminobutyric acid receptor (GABAA) ligand-gated ion channel complex. The receptor molecule is formed by the confluence of five subunit proteins. In this case, two of the subunits are of the α type, two β and one γ, although many combinations of the 20 known subunits are possible. Globular regions of the protein stick out from the membrane on the extracellular side, and the interfaces between these regions are targets for GABA and for the benzodiazepines and related drugs. The protein domains that span the outer cell membrane are depicted as cylinders. These regions are thought to be targets for general anesthetics (e.g., propofol) neurosteroids, and alcohol. A hole in the middle of the five subunits is the ion conduction pathway, or channel pore.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3860493&req=5

f4-arh-31-3-196: Schematic drawing of the γ-aminobutyric acid receptor (GABAA) ligand-gated ion channel complex. The receptor molecule is formed by the confluence of five subunit proteins. In this case, two of the subunits are of the α type, two β and one γ, although many combinations of the 20 known subunits are possible. Globular regions of the protein stick out from the membrane on the extracellular side, and the interfaces between these regions are targets for GABA and for the benzodiazepines and related drugs. The protein domains that span the outer cell membrane are depicted as cylinders. These regions are thought to be targets for general anesthetics (e.g., propofol) neurosteroids, and alcohol. A hole in the middle of the five subunits is the ion conduction pathway, or channel pore.
Mentions: Steroid hormones––small, complex molecules involved in intercellular communication—are highly lipid soluble and have a variety of actions in the body and brain. For example, corticosteroids are released from the cortex of the adrenal glands located on top of the kidneys in response to external stress and are carried by the bloodstream to their sites of action throughout the body and brain (Brunton et al. 2005). It now is widely appreciated that steroids have two mechanisms of action. The traditional steroid signaling pathway involves an intracellular steroid receptor that resides in the cytosol when unbound and translocates to the cell nucleus when it is bound with the steroid (Brunton et al. 2005; Hayashi et al. 2004) (see figure 3C). The receptor protein then can bind to DNA and directly influence the transcription of a variety of genes. The second type of steroid hormone signaling involves actions on cell surface receptors. For example, derivatives of the sex steroid progesterone interact with the A-type receptors for the neurotransmitter γ-aminobutyric acid (GABA) (i.e., GABAA receptors) to enhance receptor function allosterically by producing a conformation, or shape, change in the receptor (Mitchell et al. 2008) (see figure 4). The so-called neurosteroids that act within the brain can be generated locally within CNS tissue and thus can have paracrine2 as well as endocrine actions.

Bottom Line: Hundreds of molecules are known to act as neurotransmitters in the brain.Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones.It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Integrative Neuroscience at the National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland.

ABSTRACT
Nerve cells (i.e., neurons) communicate via a combination of electrical and chemical signals. Within the neuron, electrical signals driven by charged particles allow rapid conduction from one end of the cell to the other. Communication between neurons occurs at tiny gaps called synapses, where specialized parts of the two cells (i.e., the presynaptic and postsynaptic neurons) come within nanometers of one another to allow for chemical transmission. The presynaptic neuron releases a chemical (i.e., a neurotransmitter) that is received by the postsynaptic neuron's specialized proteins called neurotransmitter receptors. The neurotransmitter molecules bind to the receptor proteins and alter postsynaptic neuronal function. Two types of neurotransmitter receptors exist-ligand-gated ion channels, which permit rapid ion flow directly across the outer cell membrane, and G-protein-coupled receptors, which set into motion chemical signaling events within the cell. Hundreds of molecules are known to act as neurotransmitters in the brain. Neuronal development and function also are affected by peptides known as neurotrophins and by steroid hormones. This article reviews the chemical nature, neuronal actions, receptor subtypes, and therapeutic roles of several transmitters, neurotrophins, and hormones. It focuses on neurotransmitters with important roles in acute and chronic alcohol effects on the brain, such as those that contribute to intoxication, tolerance, dependence, and neurotoxicity, as well as maintained alcohol drinking and addiction.

Show MeSH
Related in: MedlinePlus