Adrenergic Receptors Overview

Catecholamines are neurotransmitters, including noradrenaline and adrenaline, that bind to adrenergic receptors to mediate physiological responses.

Adrenergic receptors play a key role in the sympathetic nervous system, mediating responses such as increased heart rate and blood pressure.

Catecholamines are synthesized by sequential modifications of tyrosine, leading to the production of dopamine, noradrenaline, and adrenaline.

<p>Non-adrenergic, non-cholinergic receptors include receptors for neurotransmitters like GABA, 5-HT, and dopamine, which also mediate various physiological effects.</p> Signup and view all the answers

<p>Adrenergic receptor pharmacology often involves drugs that modulate responses to catecholamines, while cholinergic pharmacology focuses on acetylcholine.</p> Signup and view all the answers

<p>Presynaptic α2 receptors function as part of a feedback mechanism to control neurotransmitter release.</p> Signup and view all the answers

<p>β1 adrenoceptors increase contractility through the phosphorylation of Ca2+ channels, enhancing calcium influx.</p> Signup and view all the answers

<p>β2 adrenoceptors lead to relaxation of smooth muscle by promoting cAMP production and subsequent phosphorylation of contractile proteins.</p> Signup and view all the answers

<p>β3 adrenoceptors primarily stimulate lipolysis, leading to the breakdown of triglycerides into free fatty acids.</p> Signup and view all the answers

<p>All β adrenoceptors are Gs-coupled GPCRs that activate adenylate cyclase, leading to increased cAMP levels and PKA activation.</p> Signup and view all the answers

<p>Monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT).</p> Signup and view all the answers

<p>VMAT is involved in recycling catecholamines back into vesicles, while NET is responsible for their reuptake.</p> Signup and view all the answers

<p>MAOIs inhibit the breakdown of catecholamines, leading to increased levels; excessive intake of tyramine can cause hypertensive crisis.</p> Signup and view all the answers

<p>MAO-A typically breaks down catecholamines, whereas MAO-B has a different specificity for various monoamines.</p> Signup and view all the answers

<p>Adrenergic receptors are G-protein coupled receptors, classified into two main classes: α and β adrenoceptors.</p> Signup and view all the answers

<p>5-HT1 is a Gi/Go receptor and its primary effect is a decrease in cAMP.</p> Signup and view all the answers

<p>5-HT3 receptors are ligand-gated sodium and potassium channels that result in depolarization of the plasma membrane.</p> Signup and view all the answers

<p>SSRIs increase serotonin levels by selectively inhibiting its reuptake.</p> Signup and view all the answers

<p>Monoamine oxidase breaks down monoamines, including serotonin, thereby inhibiting serotonergic transmission.</p> Signup and view all the answers

<p>The two types of dopamine receptors are D1-like receptors and D2-like receptors, both of which are GPCRs.</p> Signup and view all the answers

<p>5-HT2 receptors increase levels of IP3 and DAG, leading to excitatory responses.</p> Signup and view all the answers

<p>5-HT3 receptor antagonists such as Dolasetron, Granisetron, and Ondansetron can be used as antiemetics.</p> Signup and view all the answers

<p>TCAs are non-selective reuptake inhibitors, affecting the uptake of both serotonin and norepinephrine.</p> Signup and view all the answers

<p>D1-like receptors are coupled to Gs, while D2-like receptors are coupled to Gi.</p> Signup and view all the answers

<p>Dopamine receptors are involved in motivation and pleasure.</p> Signup and view all the answers

<p>Levodopa is a precursor to dopamine that elevates dopaminergic signaling by crossing the blood-brain barrier.</p> Signup and view all the answers

<p>Antipsychotics mostly antagonize the D2 receptor to mitigate dopaminergic signaling.</p> Signup and view all the answers

<p>ATP can also act as an excitatory neurotransmitter via purinoceptors.</p> Signup and view all the answers

<p>P2X is a ligand-gated ion channel that responds to ATP.</p> Signup and view all the answers

<p>Functions include nociception, platelet aggregation, and vascular endothelial cell-mediated vasodilation.</p> Signup and view all the answers

<p>P2Y antagonists, such as Clopidogrel, are used as antiplatelet agents to inhibit blood clot formation.</p> Signup and view all the answers

<p>GABA is the main inhibitory neurotransmitter; it causes hyperpolarization of neurons by promoting the influx of Cl- ions, making the neuron negatively charged and unable to fire.</p> Signup and view all the answers

<p>The two types of GABA receptors are GABAA, which is an ion channel, and GABAB, which is a G protein-coupled receptor (GPCR). GABAA mediates fast synaptic inhibition while GABAB is involved in slower, modulatory responses.</p> Signup and view all the answers

<p>Benzodiazepines act as positive allosteric modulators, enhancing GABA signaling by binding to the GABAA receptor and increasing Cl- influx, but they require the presence of GABA to function.</p> Signup and view all the answers

<p>Ethanol increases GABA-mediated Cl- influx by acting on GABAA receptors, thereby enhancing the inhibitory effects of GABA and contributing to its sedative properties.</p> Signup and view all the answers

<p>Serotonin, also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter synthesized from the amino acid tryptophan.</p> Signup and view all the answers

<p>Serotonin is involved in mood regulation, pain perception, and the modulation of sleep-wake cycles.</p> Signup and view all the answers

<p>Pre-synaptic inhibitory autoreceptors regulate serotonin release by sensing the amount of serotonin in the synaptic cleft and providing feedback to inhibit further release.</p> Signup and view all the answers

<p>Serotonin is cleared from the synaptic cleft through reuptake mechanisms involving serotonin transporters and breakdown by monoamine oxidase (MAO).</p> Signup and view all the answers