The involvement of corticosteroids in the supersensitivity produced in the rat anococcygeus muscle by morphine withdrawal, thyroidectomy or a single dose of reserpine.

The effects of chronically administered corticosterone on the responses of the rat isolated anococcygeus muscle to agonists (acetylcholine, norepinephrine) were compared with those of morphine withdrawal in intact or metyrapone-pretreated rats and with those of a single dose of reserpine in intact or adrenalectomized rats. The possibility that the similar supersensitivity, which occurs in thyroidectomized rats, might be associated with elevated corticosterone levels was investigated by measuring fluorimetrically the plasma levels of corticosterone in thyroidectomized rats. Corticosterone, morphine withdrawal or a single dose of reserpine produced similar supersensitivities, characterized by increased maximum responses to both agonists (acetylcholine, norepinephrine) and an increased pD2 value for acetylcholine.

The absence of cocaine- and 6-hydroxydopamine-induced supersensitivity to oxymetazoline in the rat anococcygeus muscle.

Neither cocaine nor 6-hydroxydopamine potentiated the responses of the anococcygeus muscl_ to oxymetazoline, suggesting that the specific supersensitivity to noradrenaline produced by these drugs is due to abolition of neuronal uptake mechanisms.

The effects of drugs on the sensitivity of the rat anococcygeus muscle to agonists.

1. The effects of cocaine, 6-hydroxydopamine (6-OHDA), reserpine and 17-beta-oestradiol on the sensitivity of the rat anococcygeus muscle to noradrenaline (NA), acetylcholine (ACh) and KCl were investigated.2.

In-situ and invasive carcinoma of the colon in patients with ulcerative colitis.

Four cases are described in which ulcerative colitis was complicated by carcinoma and in which the extent of the accompanying in-situ carcinoma (precancer) was determined. The extent of the in-situ carcinoma was very variable and in all cases the rectum was spared in whole or part. Search for in-situ carcinoma in rectal biopsies will fail to indicate the development of malignancy in some patients with ulcerative colitis.

Intrafollicular amyloid in primary hyperparathyroidism.

The histology of the parathyroids from 88 cases of primary hyperparathyroidism has been reviewed in a search for local amyloid deposits. Characteristic intrafollicular amyloid deposits of varying extent were found in nine cases. The case histories of these show that seven had suspected or proven pluriglandular adenomatosis but that the remainder had no such associations.