Effects of aging on alpha 1-adrenoceptor mechanisms and the inhibitory effect of diltiazem on noradrenaline maximum response in isolated rat aortic preparation

The effects of aging on alpha 1-adrenoceptor mechanisms in aortic preparations isolated from 3-, 6-, 10-, 18-, and 40-week-old rats were studied and compared with serotonin receptor mechanisms in the same preparations. The potency (pD2 value) of noradrenaline increased with age from 3 to 10 weeks, but decreased thereafter with age from 10 to 40 weeks. The affinity (pKA value) of noradrenaline and of prazosin (pA2 value) did not alter with aging. The change in potency or the pD2 value of noradrenaline was proportional to receptor reserve (pD2-pKA value) for noradrenaline, suggesting that the change of potency of noradrenaline with age was due to a change of receptor reserve, but not to change of drug affinity to alpha 1-adrenoceptors. The potency (pD2 value) and affinity (pKA value) of serotonin, and the affinity (pA2 value) of ketanserin, did not alter with aging, suggesting that serotonin receptor mechanisms in rat aorta did not change with age. The inhibitory effect of diltiazem on noradrenaline maximum response decreased with age from 3 to 10 weeks, but increased with age from 10 to 40 weeks. An inverse relationship between changes of diltiazem inhibition and receptor reserve of noradrenaline was found. Diltiazem's inhibitory effect on serotonin maximum response did not alter with aging.     

Polyclonal B-cell stimulative and immunosuppressive activities at different developmental stages of Trypanosoma gambiense

Bloodstream trypomastigote and cultured procyclic (insect midgut) forms of a monomophic strain of Trypanosoma gambiense were tested for their abilities to induce polyclonal B-cell activation (PBA) and immunosuppression (IS) in mice. Injection of a cell homogenate of bloodstream trypomastigotes induced both PBA and IS, while neither PBA nor IS was observed in mice injected with a cell homogenate of cultured procyclics. The results indicate that the substance(s) inducing PBA or IS is related to the developmental stage of the parasites.     

Eyelid reconstruction in pachydermoperiostosis

Our experience with an unusual case of pachydermoperiostosis is described. This case was accompanied by enlargement of the eyelids, excessive secretions, and difficulty in opening the eyes. Partial and serial excisions of the upper and lower eyelids were done to correct the thickened eyelids. As a result of the operations, this patient can open his eyes fully and the secretions have decreased.     

Changes in the content of atrial natriuretic factor with the progression of hypertension in spontaneously hypertensive rats

In order to assess possible roles of atrial natriuretic factor (ANF) in spontaneously hypertensive rats (SHR), we examined the content of immunoreactive-ANF in plasma, the atria, hypothalamus and pons of SHR and Wister Kyoto (WKY) rats by radioimmunoassay at different stages of age. With the progression of hypertension, plasma concentration of ANF increased whereas it decreased in the atria in SHR. This suggests ANF is secreted in response to hypertension. On the other hand, at hypothalamus and pons, ANF content was significantly higher in SHR than in WKY rats. This finding suggests possible involvement of ANF in the central regulation of blood pressure.