lecture 3 Flashcards
what are the 3 cases of neurotransmitters release in the autonomic nervous system
- ach if released from the pre-synaptic neuron
- ach if released from a parasympathetic post synaptic neuron
- NE,E if released from a sympathetic neuron or dopamine if released from a dopaminergic sympathetic neuron
what kind of receptors are adrenergic receptors
g coupled receptors
what are the three ways NE can be removed from the synapse
- COMT- metabolized by post synaptic catechol-o-methyltransferase
- can be transported back into the neuron
- it can diffuse from the synaptic cleft and be metabolized in the plasma, liver, excreted in urine
the target tissue receptors for the PSNS and the SNS are
muscarinic for PSNS and adrenergic for SNS
drugs that act similarly to endogenous catecholamines are called
sympathomimetics/ adrenergic agonist
alpha 2 agonists are sedatives and analgesics that_____, and are good for?
decrease cardiac output
good for premeding
good for standing procedures
since alpha 2 agonists decrease cardiac output, can you use them in a patient with compromised CV function? why or why not?
no, reducing the dose does not reduce the magnitude of the adverse effects
how do alpha 2 agonists provide sedation and analgesia?
sedation is due to inhibition of NE release in the brainstem, analgesia is due to reduced NT release and signal transmission in afferent pathways
why do alpha 2 agonist reduce cardiac output
since the alpha 2 agonist will initially constrict the vessels, blood pressure increases, responding to high blood pressure the body will want to slow the hard so parasympathetic tone will cause bradycardia
what is xylazine? what’s it used for? what are it’s side affects? what do you reverse it with? how long does it last?
xylazine- alpha 2 agonist
sedative commonly used in horses and ruminants
side effects include- AV block, sweating, reduced GI motility, increased myometrial tone (premature delivery be careful in late pregnant animals)
reversed with yohimbine or atipamezole
half life is 50 min, with full recovery 2-3 hours after sedation
the common large animal a2a are xylazine, detomidine, and romifidine, do their sedative effects last longer than their analgesic effects?
yes, in these alpha 2 agonist the sedative effects last longer
what is detomidine? what’s it used for? what are it’s side affects? what do you reverse it with? how long does it last?
another alpha 2 agonist
used mostly in horses, can use in cattle, better for more painful standing surgery as it is 50-100x more potent than xylazine
safer use in pregnant animals
can be reversed with a2antagonist like atipamezole
half life of 25 min
what is dexmedetomidine? what’s it used for? what are it’s side affects? what do you reverse it with? how long does it last?
an alpha 2 agonist
the most selective a2a
used commonly in small animals for sedation and reduces maintenance anesthetic needs when used as pre med
reverse with atipamezole
makes cats vomit
what is dobutamine? what’s it used for? what are it’s side affects? how long does it last?
a beta 1 agonist
positive inotrope that does not increase heart rate
half life is 2 min given as cri
trachycardia at high doses and should not be used in cats as it causes seizures
what is clenbuterol? what’s it used for? what are it’s side affects? what do you reverse it with? how long does it last?
beta 2 agonist
bronchodilator sometimes used to treat equine asthma, inhibits uterine tone contractions
BANNED IN FOOD ANIMALS
