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To investigate the possible interaction of a beta adrenergic blocking agent and marihuana, six healthy experienced marihuana smokers received the two drugs separately and in combination. Propranolol (120 mg per os) reduced resting HR and BP; there were no changes in performance on tasks designed to test psychomotor speed, attention, memory and learning. Marihuana (10 mg delta9-THC), administered in smoke, induced the typical subjective state ("high") with marked increases in HR, BP and conjunctival injection; it impaired performance on a learning test without significantly affecting attention. Pre-treatment with propranolol blocked effectively the cardiovascular effects of marihuana; it prevented the learning impairment and, to a lesser degree, the characteristic subjective experience.

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The hypothesis of visceral learning has opened a new avenue in the search for a pathway between psychosocial stimuli and physiological changes. To apply this approach to asthma required a technique for the measurement of the airways' patency, which could be interfaced with the strategy of visceral learning. The method of forced oscillations was shown to correlate highly with whole body plethysmography. The rapid output of the instrument was used on line to control a visual reinforcement signal. Forty-six mild asthmatics, blind to the effect sought in order to minimize the role of suggestion, were tested in a series of evolving experiments. In the first series, two groups of subjects (N=15,13) were able, with this sensory feedback, to decrease (p less than 0.01) their total respiratory resistance; subsequently a smaller group of subjects (N=5), who received reinforcement signals unrelated to the state of their airways, showed no such change. Similar results were obtained in the second series of tests; in A-B-B-A order, the subjects (N=13) received either contingent or noncontingent reinforcement; furthermore, the reinforcement was available only if their lung volume was within the range observed during baseline.