الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
The first part of this investigation was concerned with the effect of pethidine on 8ympathetic and neuro— muscular transmission. In conjunction with this, the following points were revealed.
1) Pethidine induced a dual effect on the isolated innervated rabbit intestine; an augmentation, at low concentration, end blockade, at high concentration, of sympathetic transmission. At the same time pettiidine blocked sympathetic transmission in guinea pig vas deferens and rat anococcygeal muscle.
The augmentation of sympathetic activity is
probably due to blockade of neuronal uptake of nor—
adrenaline whereas the blockade of sy-mpatbetic transmission seems to involve both a decrease in noradrenaline release and blockade of poatsynaptic c(—adrenergic receptors.
2) Pethidine prevented the adrenergic neurone blockade induced by the entihypertenaive drug guanethidine
but failed to reverse its established blockade.
At the neuromuscular junction, petbidine had a dual effect.
a) In the cat tibialis muscle preparation and, at low concentration, in the rat diaphragm, it potentiated the indirect muscle twitches; an effect which is probably due to local anaesthetic activity.