II. Effects: Alpha Receptor General

  1. Vascular smooth muscle
    1. Skin and skeletal muscle vessel constriction
    2. Splanchnic vessel constriction
  2. Gastrointestinal
    1. Myenteric Plexus Inhibition
  3. Genitourinary
    1. Pregnant Uterus contraction
    2. Penis and seminal Vesicle ejaculation
  4. Skin
    1. Pilomotor smooth muscle contraction
    2. Apocrine gland contraction
  5. Metabolic
    1. Gluconeogenesis
    2. Glycogenolysis

III. Effects: Alpha 1 Receptors

  1. Vascular smooth muscle postsynaptic Neurons
    1. Vasoconstriction
  2. Myocardium
    1. Positive Inotrope
    2. Negative Chronotrope
  3. Eye
    1. Radial muscle contraction
  4. Gastrointestinal and Genitourinary
    1. Sphincter (e.g. anus) contraction

IV. Effects: Alpha 2 Receptors

  1. Peripheral Alpha 2 Receptors
    1. Vascular Smooth Muscle (mixed effect)
      1. Modulates large vessel tone
      2. Arteriolar and venous Vasoconstriction
      3. Opposes alpha 1 receptor Vasoconstriction
        1. Inhibits Norepinephrine release
        2. Decreases adrenergic activity
    2. Gastrointestinal
      1. Smooth muscle wall relaxation
    3. Metabolic
      1. Fat Cell Lipolysis
  2. Central Alpha 2 Receptors (CNS)
    1. Inhibits Locus Ceruleus reflex arc
    2. Peripheral vasodilatation

V. Medications: Alpha Adrenergics

  1. Alpha Adrenergic Agonist (Alpha Adrenergic Receptor)
    1. Alpha Non-Specific
      1. Epinephrine
      2. Norepinephrine
    2. Alpha 1 Selective
      1. Phenylephrine
      2. Methoxamine
    3. Alpha 2 Selective
      1. Clonidine (See Central Adrenergic Agonist)
      2. Alpha-methylnorepinephrine
  2. Alpha Receptor Antagonist
    1. Alpha Non-Specific
      1. Phentolamine
    2. Alpha 1 Selective
      1. Prazosin (See Alpha Adrenergic Antagonist)
      2. Phenoxybenzamine
    3. Alpha 2 Selective
      1. Yohimbine
      2. Tolazoline

Images: Related links to external sites (from Google)

Ontology: Receptors, Adrenergic, alpha-1 (C0001638)

Definition (MSH) A subclass of alpha-adrenergic receptors that mediate contraction of SMOOTH MUSCLE in a variety of tissues such as ARTERIOLES; VEINS; and the UTERUS. They are usually found on postsynaptic membranes and signal through GQ-G11 G-PROTEINS.
Concepts Receptor (T192) , Amino Acid, Peptide, or Protein (T116)
MSH D018340
English Adrenergic Receptor, alpha-1, Adrenergic Receptors, alpha-1, alpha 1 Adrenergic Receptors, alpha-1 Adrenergic Receptor, alpha-1 Adrenergic Receptors, Receptor, alpha-1 Adrenergic, Receptors, alpha-1 Adrenergic, Receptor, Adrenergic, alpha-1, alpha 1 Adrenergic Receptor, Adrenergic alpha-1 Receptors, Receptors, Adrenergic, alpha-1, Adrenergic Receptor, alpha 1, Receptors, Adrenergic alpha-1, Receptors, alpha 1 Adrenergic, alpha-1 Receptors, Adrenergic, RECEPT ADREN ALPHA 1, ALPHA 1 ADREN RECEPT, ADRENERGIC RECEPTORS ALPHA 01, ADREN ALPHA 1 RECEPT, ALPHA ADRENERGIC RECEPTORS 01, RECEPTORS ALPHA 1 ADRENERGIC, RECEPT ALPHA 1 ADREN, Receptors, Adrenergic, alpha-1 [Chemical/Ingredient], Adrenergic alpha 1 Receptors
Swedish Alfa-1-adrenerga receptorer
Finnish Alfa-1-adrenergiset reseptorit
Russian ADRENERGICHESKIE AL'FA-1 RETSEPTORY, RETSEPTORY ADRENERGICHESKIE AL'FA-1, RETSEPTORY AL'FA-1 ADRENERGICHESKIE, AL'FA-1 ADRENERGICHESKIE RETSEPTORY, АДРЕНЕРГИЧЕСКИЕ АЛЬФА-1 РЕЦЕПТОРЫ, АЛЬФА-1 АДРЕНЕРГИЧЕСКИЕ РЕЦЕПТОРЫ, РЕЦЕПТОРЫ АДРЕНЕРГИЧЕСКИЕ АЛЬФА-1, РЕЦЕПТОРЫ АЛЬФА-1 АДРЕНЕРГИЧЕСКИЕ
Italian Recettore alfa-1 adrenergico, Recettori alfa-1 adrenergici
German REZEPTOREN ALPHA 1 ADRENERGE, ALPHA ADRENERGE REZEPTOREN 01, ADRENERGE REZEPTOREN ALPHA 01, Adrenerge Alpha-1-Rezeptoren, Alpha-1-adrenerge Rezeptoren, Rezeptoren, Alpha-1-adrenerge, Rezeptoren, adrenerge, Alpha-1-
French Récepteurs alpha-1 adrénergiques
Czech receptory adrenergní alfa-1, alfa-1-adrenergní receptory, alfa-1-adrenoreceptory
Spanish Receptores Adrenérgicos alfa-1, Receptores Adrenérgicos alfa 1, Receptor Adrenérgico alfa 1, Receptor alfa-1 Adrenérgico, Receptores alfa-1 Adrenérgicos
Portuguese Receptores Adrenérgicos alfa-1, Receptores alfa-1 Adrenérgicos, Receptores Adrenérgicos alfa 1, Receptor alfa-1 Adrenérgico, Receptor Adrenérgico alfa 1
Polish Receptory adrenergiczne alfa 1
Japanese アドレナリンアルファ1受容体, α1受容体, アドレナリンα1受容体, アルファ1アドレナリンレセプター, アルファ1アドレナリン受容体, 受容体-アドレナリン作用性アルファ1, アドレナリン作用性アルファ1受容体, アルファ1受容体, 受容体-アドレナリンα1

Ontology: Receptors, Adrenergic, alpha-2 (C0001639)

Definition (MSH) A subclass of alpha-adrenergic receptors found on both presynaptic and postsynaptic membranes where they signal through Gi-Go G-PROTEINS. While postsynaptic alpha-2 receptors play a traditional role in mediating the effects of ADRENERGIC AGONISTS, the subset of alpha-2 receptors found on presynaptic membranes signal the feedback inhibition of NEUROTRANSMITTER release.
Concepts Receptor (T192) , Amino Acid, Peptide, or Protein (T116)
MSH D018341
English Adrenergic Receptor, alpha-2, Adrenergic Receptors, alpha-2, alpha 2 Adrenergic Receptors, alpha-2 Adrenergic Receptor, alpha-2 Adrenergic Receptors, Receptor, alpha-2 Adrenergic, Receptors, alpha-2 Adrenergic, Receptor, Adrenergic, alpha-2, Adrenergic alpha-2 Receptors, Receptors, Adrenergic, alpha-2, Adrenergic Receptor, alpha 2, Receptors, Adrenergic alpha-2, Receptors, alpha 2 Adrenergic, alpha-2 Receptors, Adrenergic, ALPHA 2 ADREN RECEPT, ALPHA ADRENERGIC RECEPTORS 02, RECEPT ADREN ALPHA 2, RECEPT ALPHA 2 ADREN, ADREN ALPHA 2 RECEPT, RECEPTORS ALPHA 2 ADRENERGIC, ADRENERGIC RECEPTORS ALPHA 02, Receptors, Adrenergic, alpha-2 [Chemical/Ingredient], alpha-2-adrenergic receptors, alpha-2-AR, Adrenergic alpha 2 Receptors
Swedish Alfa-2-adrenerga receptorer
Finnish Alfa-2-adrenergiset reseptorit
Russian RETSEPTORY ADRENERGICHESKIE AL'FA-2, ADRENERGICHESKIE AL'FA-2 RETSEPTORY, AL'FA-2 ADRENERGICHESKIE RETSEPTORY, RETSEPTORY AL'FA-2 ADRENERGICHESKIE, АДРЕНЕРГИЧЕСКИЕ АЛЬФА-2 РЕЦЕПТОРЫ, АЛЬФА-2 АДРЕНЕРГИЧЕСКИЕ РЕЦЕПТОРЫ, РЕЦЕПТОРЫ АДРЕНЕРГИЧЕСКИЕ АЛЬФА-2, РЕЦЕПТОРЫ АЛЬФА-2 АДРЕНЕРГИЧЕСКИЕ
German ALPHA ADRENERGE REZEPTOREN 02, REZEPTOREN ALPHA 2 ADRENERGE, ADRENERGE REZEPTOREN ALPHA 02, Adrenerge Alpha-2-Rezeptoren, Alpha-2-adrenerge Rezeptoren, Rezeptoren, Alpha-2-adrenerge, Rezeptoren, adrenerge, Alpha-2-
Italian Recettore alfa-2 adrenergico, Recettori alfa-2 adrenergici
French Récepteurs alpha-2 adrénergiques
Czech alfa-2-adrenergní receptory, receptory adrenergní alfa-2, alfa-2-adrenoreceptory
Spanish Receptores Adrenérgicos alfa-2, Receptores Adrenérgicos alfa 2, Receptores alfa-2 Adrenérgicos
Portuguese Receptores Adrenérgicos alfa-2, Receptores Adrenérgicos alfa 2, Receptores alfa-2 Adrenérgicos
Polish Receptory adrenergiczne alfa 2
Japanese α2受容体, アドレナリンアルファ2受容体, アドレナリンα2受容体, アルファ2アドレナリンレセプター, アルファ2アドレナリン受容体, 受容体-アドレナリン作用性アルファ2, アドレナリン作用性アルファ2受容体, アルファ2受容体, 受容体-アドレナリンα2

Ontology: alpha-adrenergic receptor (C0034784)

Definition (MSH) One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.
Definition (NCI) Expressed by Alpha Adrenergic Receptor Genes in effector tissues innervated by postganglionic sympathetic adrenergic fibers, Alpha Adrenergic Receptors are one of two major classes of adrenergic receptors (alpha and beta) based on their reactions to norepinephrine and epinephrine, on cellular effects of receptor activation, and on relative affinities and reactions to synthetic blocking or stimulating agents. Alpha-adrenergic receptors respond to blocking agents such as phenoxybenzamine and phentolamine. When coupled to adenylate cyclase through Gi protein, Alpha Adrenergic Receptor stimulation results in decreased intracellular cyclic AMP.
Definition (CSP) alpha-1 is coupled to phospholipase C, such that stimulation results in production of second messengers DAG and in inositol phosphates; alpha-2 is coupled to adenylate cyclase such that stimulation lowers cyclic AMP.
Concepts Receptor (T192) , Amino Acid, Peptide, or Protein (T116)
MSH D011942
SnomedCT 42938005
English Adrenergic alpha Receptors, alpha adrenergic receptor, alpha Adrenergic Receptors, Receptors, Adrenergic, alpha, Receptors, alpha Adrenergic, Receptor, Adrenergic, alpha, Adrenergic alpha-Receptors, Receptors, alpha-Adrenergic, alpha-Adrenergic Receptors, alpha-Receptors, Adrenergic, RECEPT ALPHA ADREN, RECEPT ADREN ALPHA, ADREN ALPHA RECEPT, ALPHA ADREN RECEPT, ADRENERGIC RECEPTORS ALPHA, alpha-Adrenergic receptor site, Alpha adrenergic receptor, Receptors, Adrenergic, alpha [Chemical/Ingredient], alpha-adrenergic receptor, alpha adrenergic receptors, Alpha adrenoceptors, alpha-Adrenergic receptor (substance), alpha-Adrenergic receptor, Alpha Adrenergic Receptor
Swedish Alfaadrenerga receptorer
Finnish Alfa-adrenergiset reseptorit
Russian RETSEPTORY ADRENERGICHESKIE AL'FA, AL'FA-ADRENERGICHESKIE RETSEPTORY, ADRENERGICHESKIE AL'FA-RETSEPTORY, AL'FA-ADRENORETSEPTORY, RETSEPTORY AL'FA-ADRENERGICHESKIE, АДРЕНЕРГИЧЕСКИЕ АЛЬФА-РЕЦЕПТОРЫ, АЛЬФА-АДРЕНЕРГИЧЕСКИЕ РЕЦЕПТОРЫ, АЛЬФА-АДРЕНОРЕЦЕПТОРЫ, РЕЦЕПТОРЫ АДРЕНЕРГИЧЕСКИЕ АЛЬФА, РЕЦЕПТОРЫ АЛЬФА-АДРЕНЕРГИЧЕСКИЕ
Italian Recettore alfa adrenergico, Recettori alfa adrenergici
German ADRENERGE REZEPTOREN ALPHA, Adrenerge Alpha-Rezeptoren, Alpha-Adrenerge Rezeptoren, Rezeptoren, Alpha-adrenerge, Rezeptoren, adrenerge, Alpha-
Croatian RECEPTORI, ADRENERGIČKI, ALFA
French Récepteurs alpha-adrénergiques
Czech alfa-adrenoreceptory, alfa-adrenergní receptory, receptory adrenergní alfa
Polish Receptory adrenergiczne alfa
Japanese アドレナリンアルファ受容体, α受容体, αレセプター, アドレナリンα受容体, アドレナリン作用性アルファ受容体, アルファアドレナリンレセプター, アルファアドレナリン受容体, アルファ受容体, 受容体-アドレナリン作用性アルファ, 受容体-アドレナリンα
Portuguese Receptores alfa Adrenérgicos, Receptores alfa-Adrenérgicos, Receptores Adrenérgicos alfa
Spanish Receptores alfa Adrenérgicos, Receptores Adrenérgicos alfa, Receptores alfa-Adrenérgicos, receptor alfa - adrenérgico (sustancia), receptor alfa - adrenérgico