INFLUENCE OF MORPHINE ON RESPIRATORY PATTERNS

Abstract

Administration of morphine in intact un-anesthetized dogs produces initial stimulation in both respiratory and somatic spheres, followed by (a) establishment of a rhythmic pattern of deep sighing respiration, (b) increase in post-sigh inhibition of eupnea, (c) reduction in amplitude of eupnea which may be a variation of (b), and (d) panting. These effects resemble those which follow decerebration. After midcollicular decerebration, morphine exerts the same general effects, which are intensifications of those already produced by decerebration. In these preparations morphine has much the same influence as vagotomy. In animals breathing apneustically morphine generally accelerates the apneustic rhythm and shortens in-spiratory breath-holding; it usually does not completely abolish apneusis.