Sept 21st, 2010

Pretty hard to get these words down since the vacation has just started! But I managed to muster the energy somehow : P


Hexamethonium
- not used clinically, but important in research

Clinical applications
- none
- but some ganglionic blockers can be used for severe hypertension

Action
- nicotinic receptor antagonist and since nicotinic receptors are widespread throughout the body, you will see many effects.
- most important is that they block the baroreceptor response by blocking the receptor at the ganglia where preganglionic and postganglionic neurons meet.
ex) alpha 1 vasoconstriction increases BP. Blocking the baroreceptor reflex will prevent reflex bradycardia.

Side Effects
- since it blocks at so many sites, there will be many potential adverse effects.
- look at First Aid. Key is that ganglionic blockers will mainly block dominant system at the organ.
ie) in the heart: mainly PANS blocked causing tachycardia as potential adverse effect

mn
- Hex = spell. So I just think of a witch casting a spell on someone. Spells don't affect one organ, they affect the entire person. So you'll see all sorts of side effects. A witch wants to weaken you, so all dominant innervation will be affected at each organ.


Epinephrine & Norepinephrine
- no need for mnemonics here since we'll see these everywhere!
- just keep in mind that Epi is a hormone secreted from the adrenal gland and has affinity to B2 receptors, whereas, NorEpi does not bind to B2 and acts mainly as a neurotransmitter.


Isoproterenol

Mechanism/Selectivity
- B1 & B2 affinity

Clinically
1) B1 stimulation for heart block/arrythmias to increase HR
2) B2 stimulation used to be used for bronchodilation in asthmatics

mn
- here, you have to keep in mind its dual action.
- I think of : IsAproRenal ... ppl who have good renal function (Pros), have 2 kidneys and kidneys are bean shaped (like B receptors)