Possible Interaction: Epinephrine and Methacholine

“After the highest dose of methacholine , a 15-min intravenous infusion of epinephrine (0.06 micrograms/kg/min) caused an 85 +/- 7% increase in SGaw in normal subjects (p less than 0.02).”

“Significant increases in plasma norepinephrine and plasma epinephrine concentrations were observed in response to methacholine administration with significant haemodynamic changes, but there was no correlation between the rise in plasma catecholamines and the haemodynamic changes.”

“PRESSOR AM INE …-----+PRESSOR AMINES adrenaline and noradrenaline) I 4 Homovanillic acid (urinary metabolite) -i Vanillylmandelic acid (urinary metabolite) In dysautonomia, the excretion of homovanillic acid is … twice normal, while the excretion of vanillylmandelic acid is about half normaLS There is an exaggerated response to infused noradrenaline and methacholine.”

“The muscarinic agonist methacholine (10-300 microM) produced concentration-dependent increases in adrenal output of epinephrine and norepinephrine.”

“VE increased by 82% after MCh and salbutamol (p less than 0.001), less dramatically after epinephrine and terbutaline at 50.5 and 31.5% (p less than 0.02 and p less than 0.001), respectively, and not at all after SCG and NS.”

“ Methacholine evoked a sustained, non‐desensitizing response in the cat adrenal , which declined to basal levels of secretion immediately after Ca2+ removal: upon Ca2+ restoration secretion was restored to the previous plateau.”

“When methacholine was administered concomitantly with adrenaline the decline in serum potassium concentration persisted, but the increase in ventricular vulnerability was completely prevented.”