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tactile stimuli were far better on the limb opposite this intact region of the cord than on the limb opposite this d~maged quadrant. With th ~. posterior columns divided, the patients could not feel the direction nor the speed of a moving tactile stimulus.

Responses of medullary raphe neurons to peripheral stimulation and to sys- temic opiates. -- S.D. Anderson, A.I. Basbaum and H.L. Fields, Brain Res., 123 (1977) 363--368

This brief paper really consists of two p a p e r s - one which shows that a large proportion of the neurons of the ventromedial medulla of the cat within the raphe nuclei and the adjacent reticular formation have somatosen- sory receptive fields and another reporting the effects of intravenously given morphine and naloxone on these neurons. These neurons were found to be firing continually. Most of them were excited by innocuous stimuli, partic- ularly by a slight brisk tap. About a seventh of these cells responded to intense stimuli that would have caused pain in man. Further, these neurons responded even more to mechanical stimuli after stimulation by intense heat applied to the peripheral field.

Morphine excited and naloxone inhibited these neurons; and this was regardless of the order in which the two drugs were given. Naloxone was more effective, often reducing the firing rate of the active neurons to a lower level than it had been before giving morphine.

Naloxone alters pain perception and somatosensory evoked potentials in nor- mal subjects. -- M.S. Buchsbaum, G.C. Davis and W.E. Bunney, Nature (Lond.), 270 (1977) 620--622

In a testing session the authors divided their normal subjects into two groups--pain sensitive and pain insensitive subjects. Naloxone or normal saline was then given intravenously to the subjects. The subjects were given painful electric shock to a forearm and had to rate the shocks as noticeable, distinct, unpleasant or very unpleasant. Evoked potentials to 4 stimuli of increasing amperage were also obtained. After naloxone the insensitive subjects found shocks more painful; they rated stimuli of lower amperage as unpleasant and judged a larger number of stimuli as unpleasant. Their evoked responses had shorter latencies. After naloxone the sensitive subjects found shocks less painful and their evoked responses had longer latencies. The authors concluded that differences between individuals in pain sensitivity may be related to differences in endorphin emission, and that endorphins play a physiological role in pain regulation.

SURGERY

Transampullary septectomy for post~cholecystectomy p a i n . - F.G. Moody, M.M. Berenson and D. McCloskey, Ann. Surg., 186 (1977) 415--423

Twenty~ight patients with chronic, incapacitating upper abdominal pain after cholecystectomy had excision of the common wall between the ter-