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Male and female rats developing spontaneous hypertension (SHR) were treated with dihydralazine and guanethidine during the prehypertensive period. A therapeutic effect lasted for 100 days after termination of therapy. Treated animals showed no cardiovascular lesions associated with hypertension in this strain. Untreated males showed a high incidence of cardiovascular lesions, as opposed to untreated females. Pulmonary lesions were the main cause of death in treated males. There were no cardiovascular lesions observable macroscopically in treated SHR animals of both sexes. We conclude that antihypertensive therapy administered in the critical period of prehypertension has a long term action.

Rats anaesthetised with Inactin, body temp. maintained at 37°C, were infused with mannitol-saline until both urine flow rate and conductivity reached a balanced state. In separate experiments under analogous conditions cardiac output was measured by dye dilution and organ flow rates by86Rb distribution. Doses of oxytocin of 3 ng or less, injected at or just below the carotid bifurcation, caused a highly significant natriuresis with increased tubular rejection, but no measureable haemodynamic changes. The same oxytocin dose given into the internal or external carotid artery above the bifurcation caused neither haemodynamic changes nor natriuresis. Injection of vasopressin, angiotensin and α-MSH at the sensitive site did not result in natriuresis in the same dosage range. Section of the sinus nerve significantly decreased the natriuretic response to oxytocin. It is suggested that the carotid body contains a specific oxytocin receptor capable of eliciting natriuresis in the rat.

Mit morphometrischen Methoden wurde beim Meerschweinchen eine quantitative Analyse von Volumen und Oberflachenareal der Ultrastrukturkomponenten der Herzvorhof-Muskulatur durchgefuhrt, die mit dem Erregungs-Kontraktions-Kopplungsvorgang und der Erschlaffung verknupft sind.

The changes in blood flow through selected brain structures and the changes in the total RNA content of cells of these structures were examined after a single administration of yeast RNA to 6-month-old male rats. The total content of ribosomal RNA in cells of the limbic system (septum, hippocampus, hypothalamus) increased 48 hrs after the administration of 100 mg i.p. yeast RNA , dropped after 7 days (in hypothalamus), 21 and 30 days (in hippocampus), 30 days (in septum). In cells of the limbic system as a whole there is a higher total RNA content in experimental rats. No changes were observed in the cells of parietal brain cortex. Blood flow increased in limbic structures 21 and 30 days after RNA administration and in septum and in hippocampus also 90 days after application. No changes were observed in parietal brain cortex, bulbi olfactorii, cerebellum and brain stem. Histochemical changes correlated positively with blood flow changes in the limbic system 14, 21, 30 and 90 days after RNA application. The body weight of experimental rats did not differ from that of control animals. The changes in haemodynamic parameters were transient and were demonstrated as fluctuations in heart rate, cardiac output, and peripheral resistance. Blood pressure experienced no changes.

A new vaginal contraceptive method that offers the ease of use with none of the potentially harmful physiologic effects of hormonal contraception was subjected to direct in vivo tests of its efficacy in immobilizing spermatozoa and preventing their entry into the cervical canal. The new contraceptive, a small ovoid only 2.8cm long and 1.4cm wide, is easily inserted into the vagina without the need for special applicators. It offers protection through the delivery of a highly effective spermicide by the effervescent formation of foam that disperses over the uterine opening. In the trials, no motile spermatozoa could be found in any samples obtained from the vagina, the os externum, or the cervical canal immediately after intercourse protected with the new agent. In no case were any sperm, even immotile sperm, observed in the cervical canal. By contrast, examination of 30 samples obtained immediately after coitus protected with another contraceptive agent (used as a control) revealed motile spermatozoa in the cervical canal in nine cases, and propulsive motility was seen on five occasions. The new contraceptive proved highly effective in preventing conception.