PowerPoint Presentation

undefined. [Audio] Hello everyone welcome to this nursing pharmacology class! My name is Alessandra Staffico. I am a pharmacist-scientist in the cardiology field and I am an Assistant Professor of Pharmacology. Today we will be discussing adrenergic agonists and central nervous system stimulants..

undefined. [Audio] On this slide you’ll find the objectives of today’s lecture. I would recommend you reading through all these points carefully..

undefined. [Audio] The nervous system is divided into two main parts: Central Nervous System: Comprising the brain and spinal cord. Peripheral Nervous System: Includes the motor neurons and sensory neurons. Today we will focus on a part of the Peripheral Nervous System specifically the autonomic nervous system which controls involuntary responses and innervates various organs in the body. The autonomic nervous system is further divided into: Sympathetic and parasympathetic Nervous System However our focus today will be on the sympathetic nervous system because the parasympathetic nervous system was already taught right?.

undefined. [Audio] The autonomic nervous system controls involuntary functions of our organs responding to environmental changes involuntarily. This is the main reason for its existence. Unlike the somatic system autonomic nervous system signaling is slower because their fibers are unmyelinated. In this depicted pathway a green presynaptic fiber which comes from the spinal cord does a synapsis with a violet postsynaptic fiber in an autonomic ganglion which further innervates the intestine. This is a demonstration of this efferent pathway's role in preparing visceral responses. Just to remind: efferent pathway means that the impulse is conducted from a nerve center towards a peripheral site. There is a complementary reading on afferent and efferent pathways through the provided link on this slide which is also accessible on your BlueLine..

undefined. [Audio] The sympathetic nervous system operates in opposition to the parasympathetic. Both systems coordinate responses to environmental stimuli ensuring the body maintains its balance or homeostasis. For example during stressful situations the sympathetic system is activated preparing the individual for the fight-or-flight response. Once the stressful situation subsides the parasympathetic system takes over allowing the body to rest and restore its homeostasis. So the main lesson here is that the sympathetic and parasympathetic systems work in opposition to regulate bodily functions..

undefined. [Audio] Let’s focus on the left side of this image: The sympathetic nervous system is anatomically organized with short preganglionic fibers (in blue) that synapse in the paravertebral ganglia with long postganglionic fibers (in red) that innervates the viscera. Sympathetic fibers are located in the thoracolumbar regions of the spine spanning from T1 to L2. This image is a map of all the actions and receptors involved in the sympathetic nervous system and I believe it will help you in memorizing them. So I highly recommend using this map for your study purposes..

undefined. [Audio] The pre-synaptic fibers (which are short and in green) synapse with the post-synaptic fibers (in red) in the paravertebral ganglia. Please pay attention that all the pre-synaptic fibers are cholinergic in the sympathetic system meaning they secrete acetylcholine. Acetylcholine stimulates the post-synaptic neuron through nicotinic receptors. Once stimulated the post-synaptic neurons secrete neurotransmitters specific to the target organ. For most organs innervated by the sympathetic fibers like the heart or blood vessels the neurotransmitter involved is norepinephrine. However exceptions exist. This is the case of as sweat glands and some blood vessels particularly renal vessels where the neurotransmitter could be either acetylcholine or dopamine. As a consequence these neurotransmitters act on muscarinic and dopaminergic receptors respectively. Also the presynaptic neuron can stimulate the adrenal gland causing the adrenal medulla to release catecholamines into the bloodstream. The catecholamines released are in the proportion of 80% epinephrine and 20% norepinephrine. Once in the bloodstream these catecholamines act on adrenergic receptors enhancing the effect of the sympathetic nervous system..

[Audio] Pause the video now and examine the figure on the right. Try to answer the crossword puzzle to help memorize the mechanisms of the sympathetic nervous system..

[Audio] I hope you did well. So let’s check the answers. Q1. The neurotransmitter released from all pre-ganglionic fibers in the sympathetic nervous system is acetylcholine. This is illustrated in the figure by the pre-synaptic neuron in green releasing acetylcholine in the ganglia to stimulate the post-synaptic neuron. Q4. The neurotransmitter that is released in post-ganglionic fibers in the renal vasculature is dopamine. As seen in the figure dopamine stimulates the renal vessels Q5. The neurotransmitter secreted in the post-ganglionic sympathetic fibers that innervate some vessels and the sweat glands is acetylcholine. This is shown in the corresponding part of the image. Q2. The main neurotransmitter released in most post-ganglionic sympathetic fibers is noradrenaline (norepinephrine) except for the noted exceptions we discussed previously. Q3. The substance that is 80% released by the adrenal medulla into the bloodstream through the activation of the sympathetic nervous system is epinephrine with the remaining 20% being norepinephrine. This epinephrine can act on adrenergic receptors enhancing the sympathetic response..

undefined. [Audio] All adrenergic receptors are of the metabotropic type meaning they are G protein-coupled receptors. These receptors are located on the membrane of target organ cells. When epinephrine binds to these receptors a conformational change occurs activating the G protein. The G protein can be either stimulatory or inhibitory. Depending on the receptor and the G-protein coupled and excitatory or inhibitory cascade occurs within the cell resulting in the pharmacological effect. Adrenergic receptors respond to both catecholamines: epinephrine and norepinephrine. In this figure the G protein coupled to the adrenergic receptor when bound to epinephrine is a stimulatory G protein. Upon receptor activation by epinephrine the stimulatory G protein activates adenylate cyclase an enzyme that converts A-T-P into cyclic A-M-P (cAMP). The increase in cAMP levels within the cell results in excitatory effects that could be translated into increased heart rate dilation of skeletal muscle blood vessels and the breakdown of glycogen into glucose depending the target organ where this receptor is located..

Autonomic nervous system: receptors. Sympatholytic drugs - Knowledge @ AMBOSS.

Autonomic nervous system: receptors. 1 1 2 2 Location Postsynaptic Presynaptic Second messenger Gq protein (Phospholipase C → IP3 + DAG) Gs protein (Adenyl cyclase: ATP → ↑AMPc) Gi protein (Adenyl cyclase: ATP → ↓AMPc) Effects Vasoconstriction (↑ blood pressure) ⎯⎯⎯ Peripheral vasodilation (↓ peripheral resistance) ↑ Platelet aggregation ⎯⎯⎯ Cardiac muscle ↑ Rate, force and conduction velocity ⎯⎯⎯ ⎯⎯⎯ Smooth muscle contraction (except sphincters): feces & urine retention ⎯⎯⎯ Smooth muscle relaxation: bronchodilation, ↓ uterine tonus, ↓ peristalsis, ↓ bladder tonus Skeletal muscle contraction ⎯⎯⎯ ↑ Glycogenolysis, ↓ lipolysis, ↓ insulin release ↑ Lipolysis, ↑ ghrelin (hunger), ↑ renin (kidneys) ↑ Gluconeogenesis, ↑ lipolysis, ↑ glycogenolysis, ↑ insulin release ↓ NE presynaptic release ↓ Lipolysis Mydriasis ⎯⎯⎯ ↑ Aqueous humor production ↓ Aqueous humor production Affinity NE > Epi Epi > NE Epi >> NE Epi > NE.

A diagram of a drug molecule Description automatically generated NE & Epi Sympathomimetics.

A diagram of a neuron Description automatically generated.

A diagram of a neuron Description automatically generated.

A diagram of a neuron Description automatically generated.

A diagram of a neuron Description automatically generated.

A diagram of a neuron Description automatically generated.

Adrenergic agonists. A diagram of a group of people Description automatically generated.

Nasal Congestion - Meaning, Causes, Symptoms and Treatment Nasal congestion.

Pathophysiology: distributive shock. A diagram of a human body Description automatically generated Vasodilator mediators = ↑ capillary permeability & tissue fluid + ↓ vascular resistance.

Pharmacological actions: epinephrine. Therapeutic uses 1. Vasoconstrictor effects: 1 receptors Vascular effects mainly in arterioles Delays absorption of local anesthetic Controls superficial bleeding 2. Cardiovascular effects: 1 and 1 receptors ↑ cardiac output: restore cardiac function during arrest (cardiogenic shock) 3. Respiratory effects: 2 receptors Bronchodilation (asthma) 4. Anaphylactic shock: 1, 2 and 1 receptors Reversion of hypotension and glotis edema (allergic response).

Reversal of hand peripheral ischaemia due to extravasation of adrenaline during cardiopulmonary resuscitation - ScienceDirect J Plast Reconstr Aesthet Surg. 2013 Sep;66(9):e260-3..

Drug interactions: epinephrine. 1. Monoamine oxidase (MAO) inhibitors Antidepressant drugs: isocarboxazid, phenelzine, selegiline, and tranylcypromine Tyramine: aged cheeses, cured or processed meats, pickled or fermented vegetables, citrus fruits (orange, grapefruit, lemon, lime, and tangerine) and alcoholic beverages MAOi prolongs and intensifies epinephrine effects..

Drug interactions: epinephrine. 1. Monoamine oxidase (MAO) inhibitors Antidepressant drugs: isocarboxazid, phenelzine, selegiline, and tranylcypromine Tyramine: aged cheeses, cured or processed meats, pickled or fermented vegetables, citrus fruits (orange, grapefruit, lemon, lime, and tangerine) and alcoholic beverages MAOi prolongs and intensifies epinephrine effects. 2. Tricyclic antidepressants Drugs: Amitriptyline (Elavil®, Vanatrip®), amoxapine (Asendin®), desipramine (Norpramin®), doxepin (Silenor®, Sinequan®), imipramine (Tofranil®, Tofranil-PM®), nortriptyline (Aventyl®, Pamelor®), Protriptyline (Vivactil®), Trimipramine (Surmontil®). 3. General anesthetics ↑ cardiac workload = ↑ O2 demand (attention to patients with coronary artery disease) 4. Necrosis after extravasation: 1 receptors Antidote: 5-10 mg of phetolamine in 10 mL sterile saline injected into the area 5. Hyperglycemia: 1 and 1 receptors Particularly in diabetic patients. Dose adjustment of anti-diabetic drugs..

Autonomic nervous system: receptors. 1 1 2 2 Location Postsynaptic Presynaptic Second messenger Gq protein (Phospholipase C → IP3 + DAG) Gs protein (Adenyl cyclase: ATP → ↑AMPc) Gi protein (Adenyl cyclase: ATP → ↓AMPc) Effects Vasoconstriction (↑ blood pressure) ⎯⎯⎯ Peripheral vasodilation (↓ peripheral resistance) ↑ Platelet aggregation ⎯⎯⎯ Cardiac muscle ↑ Rate, force and conduction velocity ⎯⎯⎯ ⎯⎯⎯ Smooth muscle contraction (except sphincters): feces & urine retention ⎯⎯⎯ Smooth muscle relaxation: bronchodilation, ↓ uterine tonus, ↓ peristalsis, ↓ bladder tonus Skeletal muscle contraction ⎯⎯⎯ ↑ Glycogenolysis, ↓ lipolysis, ↓ insulin release ↑ Lipolysis, ↑ ghrelin (hunger), ↑ renin (kidneys) ↑ Gluconeogenesis, ↑ lipolysis, ↑ glycogenolysis, ↑ insulin release ↓ NE presynaptic release ↓ Lipolysis Mydriasis ⎯⎯⎯ ↑ Aqueous humor production ↓ Aqueous humor production Affinity NE > Epi Epi > NE Epi >> NE Epi > NE.

Direct sympathomimetic drugs: alpha. Alpha agonists Norepinephrine: 1 > 2 > 2 Phenylephrine (Sudafed®): 1 Midodrine: 1 Oxymetazoline (Afrin®): 2 > 1 Clonidine (Catapres®): 2 Methyldopa (Aldomet®) : 2.

Direct sympathomimetic drugs: alpha. [image].

Watch these videos: https://www.youtube.com/watch?v=Q9yr-SSAJe4 https://www.youtube.com/watch?app=desktop&v=SLND-CsY18E.