P4- cardiovascular system (rat)

what is competitive antagonism?

binding of the antagonist to the receptor prevents binding of the agonist to the receptor.

the agonist and antagonist drugs bind to the same receptor

what is non-competitive antagonism?

agonist and antagonist bind at different sites on the same receptor

the antagonist binding reduces or prevents the effects of the agonist

what is reversible antagonism?

the agonist can displace the antagonist molecules from the receptor, so can recover its effect

what is irreversible antagonism?

covalent bonds are formed between the antagonist and the receptor. the agonist cannot displace the antagonist from the receptors and its effect is prevented

the autonomic nervous system is formed by the ______ system and ______ system

sympathetic (adrenergic);

parasympathetic (cholinergic)

what are the parasympathetic (cholinergic) roles in the body?

-constrict pupils

-saliva production

-constrict bronchi

-slow HR

-produce bile

-stim. digestion

-relaxes intestinal muscles

-stimulates sexual arousal

what are the sympathetic (adrenergic) roles in the body?

-dilate pupils

-inhibit saliva production

-relax bronchi

-increase HR

-slow digestion

-reduce intestinal muscles

-stimulate glucose release

-stimulate adrenaline production

-stimulates orgasm

the prototype of the adrenergic drugs (sympathomimetics) are the physiological catecholamines: ________________

adrenaline

noradrenaline

dopamine

what are the physiological adrenergics?

adrenaline

noradrenaline

dopamine

how do the adrenergic catecholamines (adrenaline, noradrenaline, dopamine) work?

they stimulate adrenergic receptors (alpha and beta), which leads to an increase on the neuronal activity and CNS excitation.

what are the adrenergic receptors in the body? what do each do?

alpha: vasoconstriction

beta:

B1- increased HR, contractility, conductivity

B2- smooth muscle relaxation (bronchi, intestines)

B3- lipolysis and fat mobilization

the stimulation of B1 adrenergic receptors does what?

increased HR, contractility, and conductivity

if a catecholamine activates a B2 adrenergic receptor, what is the result?

smooth muscle relaxation in the intestine and bronchi

(bronchodilation, reduced intestinal motility)

what is the effect of the stimulation of a B3 adrenergic receptor?

lipolysis and fat mobilization

what are the adrenergic agonists (sympathomimetics)?

adrenaline

noradrenaline

dopamine

what are the therapeutic uses of adrenergic agonists (adrenaline, noradrenaline, dopamine)?

-treatment of bradycardia or cardiac arrest

-prevention/control of local bleeding

-treatment of anaphylactic shock

-nasal/ocular decongestion

-prolongation of local anesthesia

-treatment of hypotension

adrenergic agonists stimulate what receptors? what is the result?

adrenergic receptors

alpha- vasoconstriction

B1- increased heart contractility, conductivity, HR

B2- smooth muscle relaxation of intestines and bronchi

B3- lipolysis and fat mobilization

what drugs stimulate the alpha and beta adrenergic receptors?

adrenaline, noradenaline, dopamine

which drugs are adrenergic antagonists (sympatholytics)?

prazosin

atenolol

propranolol

what type of drug is adrenaline?

adrenergic agonist

what type of drug is noradrenaline?

adrenergic agonist

what type of drug is propanolol?

adrenergic antagonist (non-selective beta blocker)

what type of drug is prazosin?

alpha 1 antagonist

it inhibits vasoconstriction, so promotes vasodilation

used to treat arterial hypertension and arrhythmias

what type of drug is atenolol?

B1 blocker

(adrenergic B1 antagonist)

what are the effects and uses of prazosin?

effect: vasodilation

use: treatment of arterial hypertension and heart failure

because it is an alpha 1 antagonist, so it blocks vasoconstriction

what drug is an alpha 1 antagonist?

prazosin

what drug is a B1 and B2 blocker?

propanolol

what are the effects and therapeutic uses of propanolol?

effect: decrease HR and contractility

use: hypertension treatment, antiarrhythmic

it is a B1 and B2 antagonist/blocker

what are the effects and uses of atenolol?

effect: decrease HR and contractility

use: hypertension treatment, antiarrhythmic

it is a B1 blocker/antagonist

what is the effect of dopamine?

increased catecholamine synthesis

what is the effect of tyramine?

stimulation of catecholamine release

what do tricyclic antidepressants and cocaine do?

inhibit catecholamine (adrenaline, noradrenaline) reuptake

what adrenergic modifier increases catecholamine synthesis?

dopamine

what adrenergic modifier stimulates catecholamine release?

tyramine

what adrenergic modifier inhibits catecholamine reuptake?

tricyclic antidepressants

cocaine

what is the neurotransmitter of the parasympathetic/cholinergic system?

Acetylcholine (Ach)

what are the Ach receptors, and what do they do?

nicotinic receptors: skeletal muscle contraction

muscarinic receptors: increased nervous activity, vasodilation, non-vascular smooth muscle contraction (bronchi and intestines), reduced HR and contractility

what is the effect of Ach binding to a nicotinic receptor?

skeletal muscle contraction

what is the effect of the stimulation of a muscarinic receptor?

increased nervous activity, vasodilation, non-vascular smooth muscle contraction (bronchi and intestines), reduced HR and contractility

which drugs are parasympathomimetics (cholinergic agonists)?

Ach

Pilocarpine

Methacholine

what are the effects/uses of cholinergic agonists (Ach, pilocarpine, methacholine)?

effect: stimulation of nicotinic and muscarinic receptors

uses: reduce tachycardia, glaucoma treatment, urinary retention, treatment of paralytic ileus

what type of drug is pilocarpine?

cholinergic agonist (parasympathomimetic)

what type of drug is methacholine?

cholinergic agonist (parasympathomimetic)

it increases activity of nicotinic and muscarinic receptors

it is used to reduce tachycardia, treat glaucoma, urinary retention, and treat paralytic ileus

what drugs are cholinergic antagonists (parasympatholytics)?

atropine

what type of drug is atropine?

cholinergic antagonist (parasympatholytic)

what is the effect and use of atropine?

effect: block muscarinic receptors

use: treat bradycardia after myocardial infarction, pre-anesthesia, antispasmodic in GI and urinary hypertonicity, antidote to Ache inhibitors

because it is parasympatholyic (cholinergic antagonist)

which drugs are cholinergic modifiers (have an indirect agonist action on cholinergic receptors)?

physostigmine

neostimine

they inhibit acetylcholinesterase (Ache), so increase Ach. They are used for motor paralysis and myasthenia gravis +cholinergic agonist applications

what do physostigmine and neostigmine do?

they have an indirect agonist action on cholinergic receptors because they inhibit Ache, so increase Ach

uses: same as cholinergic agonists, + used in motor paralysis and myasthenia gravis

which drug is a cholinergic antagonist (parasympatholytic)?

atropine