Catecholamines

Flashcards about Catecholamines, Neurochemistry, Neuropharmacology and Neurogenetics

Catecholamines

A group of neurotransmitters including Dopamine (DA), Norepinephrine (NE), and Epinephrine (EPI) that belong to the monoamines or biogenic amines.

Tyrosine Hydroxylase (TH)

The rate-limiting enzyme in catecholamine synthesis, determining the overall rate of DA or NE synthesis. Inhibited by high catecholamine levels.

Vesicular Monoamine Transporter (VMAT)

A specific transporter in the vesicle membrane that recognizes monoamines. It can be blocked by the drug reserpine.

Catechol-O-Methyltransferase (COMT) and Monoamine Oxidase (MAO)

Enzymes responsible for the breakdown of catecholamines.

Dopamine (DA) Autoreceptor Subtype

D2

Norepinephrine (NE) Autoreceptor Subtype

α2

Nigrostriatal Pathway

A major dopaminergic projection from the substantia nigra pars compacta (SNc) to the dorsal striatum, involved in voluntary movement. This pathway degenerates in Parkinson's.

Mesolimbic Dopamine Pathway

A dopaminergic pathway from the VTA to various structures of the limbic system.

Mesocortical Dopamine Pathway

A dopaminergic pathway from the VTA to the prefrontal cerebral cortex.

Dopamine Receptors

Five metabotropic receptor subtypes (D1 to D5) that interact with G proteins and function via second messengers.

D1-like Receptors

D1 and D5 dopamine receptor subtypes that stimulate adenylyl cyclase and synthesis of cAMP.

D2-like Receptors

D2, D3, and D4 dopamine receptor subtypes that inhibit adenylyl cyclase and synthesis of cAMP. D2 receptors also regulate membrane K+ channels.

SKF 38393

A D1 receptor agonist.

Quinpirole

An agonist that activates D2 and D3 receptors.

Haloperidol

A D2 receptor antagonist.

Locus Coeruleus (LC)

A dense collection of NE neurons in the pons that provides virtually all norepinephrine (NE) to the cerebral cortex.

Adrenergic Receptors (Adrenoceptors)

Metabotropic receptors for norepinephrine and epinephrine, including α and β subtypes.

α2-Receptors

Adrenergic receptors that reduce synthesis of cAMP (like D2 receptors).

α1-Receptors

Adrenergic receptors that operate via the phosphoinositide second-messenger system.

β1- and β2-Adrenoceptors

Adrenergic receptors that stimulate adenylyl cyclase and enhance synthesis of cAMP (like D1 receptors).

α2-Adrenoceptors in the PFC

Enhance working memory when activated.

Albuterol (Ventolin)

A selective β2-agonist used to treat bronchial asthma.

Metoprolol (Lopressor)

A β1-selective antagonist used to treat hypertension.

Prazosin (Minipress)

An α1-antagonist used to treat hypertension by blocking α1-receptors that cause blood vessel constriction.

Propranolol (Inderal)

A general β-antagonist used to treat hypertension by blocking β-receptors in the heart.