PT  - JOURNAL ARTICLE
AU  - A. H. MALONEY
AU  - A. L. TATUM
TI  - A STUDY OF THE EFFECT OF MORPHINE UPON THE RESPIRATORY CENTER
DP  - 1930 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 291--304
VI  - 40
IP  - 3
4099  - http://jpet.aspetjournals.org/content/40/3/291.short
4100  - http://jpet.aspetjournals.org/content/40/3/291.full
SO  - J Pharmacol Exp Ther1930 Nov 01; 40
AB  - 1. The depressed condition of the respiratory mechanism due to morphine intoxication is more marked in the case of the animal previously anesthetized with hypnotic drugs of the barbiturate series than with urethane, chloral hydrate or avertine. 2. Neonal or phenobarbital as anesthetics when followed by morphine are apt to produce serious respiratory embarrassment and even death—a condition that is not so frequently observed with the use of amytal or of ethyl-methyl-1-butyl barbituric acid. 3. Fatigue changes occur at some point or points in the respiratory reflex arc due to too great frequencies of periods of stimulation. Such fatigue or relative refractivity is made evident by an appreciable impairment in the efficiency of impulses when stimuli are applied too close together. This factor, if not taken into account, is apt to render the interpretations equivocal. 4. In small doses morphine acts as a central respiratory depressant reducing the responsiveness of that center to acceleratory afferent nervous impulses, and to carbon dioxide as the respiratory hormone. On the other hand, it increases the effectiveness of inhibitory vagal impulses, a fact which we interpret as another manifestation of a depressed respiratory center.