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EXPERIMENTAL PHARMACOLOGY 



Fig. 214. Tracing showing the action of morphine (and adrenaline) on the rate 

 of oxygen consumption, on the bronchioles, respiration and blood-pressure in a dog. 

 At the point marked "bronch. contract." in the upper record it will be seen that the 

 curve actually turns downward for a short distance. This is due to the marked con- 

 traction of the bronchioles forcing a part of the supplemental (or reserve) air out of the 

 lungs. This is probably also reflected on the respiratory tracing by limiting the expan- 

 sion of the chest. Adrenaline counteracts this broncho-constricting action of morphine 

 and the three injections of adrenaline each causes a marked increase in the depth of 

 respiration which lasts approximately during the period that the action of the adrenaline 

 can be seen on the blood-pressure. Experimentally it has been shown by Guber at 

 Zurich that animals poisoned by a minimal fatal dose of morphine recover if they be in- 

 jected with adrenaline. How would you explain the prevention of death (from the 

 morphine) in these cases by adrenaline? 



