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Dopaminergic Agonists and Antagonists - Coggle Diagram
Dopaminergic Agonists and Antagonists
Agonists
apomorphine
D1 and D2 DAR
acts in CNS to produce vom in dogs
bromocriptine or cabergoline
D2 DAR
inhibit ACTH secre from pit adenomas in an w/ Cushing's dz
dopamine
D1 and D2 DAR
pos inotrope
vasoconstrictive activity
vasodila of renal blood ves
maint renal blood flow and diuresis in circu shock, acute heart failure and other severe hypotensive states
fenoldopam
peripj D1 DAR
vasoldila of renal arterioles
maint renal blood flow and diuresis in circu shock, acute heart failure and other severe hypotensive states
Antagonists
acepromazine
partially selective D2 DAR
maj tranq
ani tranq and beh problems
Dopamine receptors (DAR)
D1-like
inc cAMP
CNS
dila of renal blood ves
D2-like
dec cAMP
CNS
sympa n terminals
dec NE release
Major tranquilizers
competitively block DAR in CNS pthwy
tranq DA antagonist produce ataraxia
beh quieting, indiff to pscyho stressors and reduced spont mvmts
DOES NOT ACTUALLY REDUCE PAIN, AGGRESSION OR ANXIETY
rapid effects
indications
short term admin on as needed basis
tempor dec motor responses assoc w/ fear or compulsive beh
"typical" maj tranq
uses
sedate ani prior to gen anesth
immobiliz of wild lg ani in combo w/ opiod drug
anti-emetic actions, esp in dogs
acepromazine
phenothiazine class
block D2 DAR
"off target" blockage of muscarinic cholinergic, H1-histamine and alpha-adrenergic recep
onset: 10 min post IV injection
hepatic metab
contraindications
ani w/ cardiovascu instabil
use caution when admin w/ other CNS depressant or anesthetic drugs
side effects
hypothermia
bradycardia and hypotension
sedation or paradoxical excitability
blood dyscrasias
azoperone and haloperidol
butyrophenones
block D2 DAR
gen side effects
motor deficits
tremors, stiffness, musc spasms
bradycardia and hypotension due to alpha-adrenergic blockage
inc secre of prolactin and other pit horm
may paradoxically inc aggressive beh
newer, "atyp" drugs have less side effects