Location and function of the so-called interneurons of rat lateral geniculate body.

Attempts were made to locate in terms of stereotaxic coordinates or histologically the so-called interneurons of the lateral geniculate body in urethane-anesthetized rats. Interneurons were identified as the units that were fired in burst by single-shock stimulations of optic tract and optic radiation. Most interneurons were recorded from a restricted area separate from but immediately rostral to the area containing relay cells (principal cells). The latter were the units which were fired antidromically by optic radiation stimulation and showed usually only one spike discharge in response to optic tract stimulation. Histologically the recording sites of interneurons were located in the nucleus reticularis thalami in the immediate vicinity of the dorsal nucleus of the lateral geniculate body. By quasi-intracellular recordings from principal cells it was found that single-shock stimulation of a group of interneurons elicited IPSPs that were effective to make principal cells unresponsive to optic tract stimuli and to arrest the cells' spontaneous discharges. The refractoriness of principal cells after excitation by optic tract impulses was proved to be due to the activities of interneurons, because it was virtually absent after an electrolytic lesion had been produced in the area of interneurons. These findings are interpreted as a substantial basis for qualifying interneurons as an inhibitory element of principal cells.     

A case of adenomatosis coli complicated with malignant lymphoma of the spleen

A case of adenomatosis coli complicated with malignant lymphoma of the spleen is described herein. An increase in the serum lactic dehydrogenase level of a 50 year old female was noted 9 years after she underwent a total colorectal resection for adenomatosis coli complicated by cancer. A tumor was observed in the spleen on CT and ultrasonography, and a diagnosis of malignant lymphoma was subsequently made by biopsy. At the time of splenectomy, no extension of the tumor was observed in any other organs and it was found histologically to be large cell type follicular lymphoma. A review of the 903 patients with adenomatosis coli documented in Japan revealed the occurrence of mesodermal malignant tumors to be considerably high. Hence, adenomatosis coli appears likely to be a causative factor in malignant lymphoma of mesodermal origin.     

Cervical sympathectomy affects adrenocorticotropic hormone and thyroid-stimulating hormone in rats

To examine the effects of bilateral cervical sympathectomy on the secretion of adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), and prolactin (PRL), 18 male rats were divided into three groups: control (Cont), sham operation (Sham), and bilateral cervical sympathectomy (Symp). All rats were kept under a normal circadian rhythm for 2 weeks. Subsequently, blood was collected and plasma ACTH as well as serum TSH, GH, and PRL levels were measured. The difference in ACTH levels between the Cont and Sham groups was not significant, but ACTH levels in the Symp group were significantly higher than those in the other groups. The difference in TSH levels between the Cont and Sham groups was also not significant, but TSH levels in the Symp group were significantly lower than those in the Cont group. There were no statistically significant differences in GH and PRL levels among these groups. The present results suggest that cervical sympathectomy in the rat increases ACTH secretion and decreases TSH secretion in the pituitary. These effects seem to be due to a mildly increased secretion of melatonin in the pineal body that probably in turn increases corticotropin-releasing factor (CRF) secretion and decreases thyrotropin-releasing hormone (TRH) secretion in the hypothalamus. Extrapolation of these findings to humans suggests that longterm and repeated stellate ganglion block would affect the pituitary secretions of ACTH and TSH.