A study was attempted to establish a screening method for detecting cholelitholytic ingredients from a wide variety of natural substances. Although mice were selected as a suitable pathological model of cholelithiasis to detect a small amount of the ingredients, all the conventional lithogenic diets caused unfavorable influence on the animals. Therefore, as the first step we formulated a new lithogenic diet consisting of butter, cholesterol, cholic acid, etc, which was adequate for mice. Subsequently, the pathological characteristics and persistence of cholelithiasis were examined in the animals; the changes in bile compositions including free and conjugated bile acids, cholesterol and phospholipids were observed before and at the onset of cholelithiasis. Following confirmation of the stone formation, a normal diet was substituted for the lithogenic diet to likewise assess the bile compositions 4 and 6 weeks later. An increasing tendency for deoxycholic acid, disappearance of chenodeoxycholic acid and decrease in ursodeoxycholic acid were seen under the condition of cholelithiasis. In addition, the cholic acid-glycine conjugate which should not exist in the normal state and the increase in free and tauring-conjugated cholic acid were noticed. The biliary cholesterol level in treated mice increased to about 4 times higher than that in untreated mice, while the biliary phospholipids and total bile acids levels increased to only about 1.5 and about 2 times the control levels, respectively. The incidence of stone formation rose sharply at an experimental period between 2 and 3 weeks after starting the lithogenic diet. Gallstones did not disappear even at the 6th week after substituting a normal diet for the lithogenic one. However, the cholic acid-glycine conjugate disappeared, and deoxycholic acid as well as chenodeoxycholic acid and ursodeoxycholic acid tended to recover to the normal levels in the bile.

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Effects of β-blockers on the blood pressure (BP), urinary output (V) and excretion of Na⁺ (U_NaV) and K⁺ (U_KV) were studied in DOCA-saline hypertensive rats in comparison with those of a thiazide diuretic drug, penfluzide. Pindolol produced a hypotension at all infusion rates of Ringer's solution used and a decrease in V with a retention of Na⁺ and K⁺ at a low infusion rate. There was a parallel shift of Guyton's renal function curve back to the lower pressure ranges. Similar effects were observed with labetalol. Propranolol induced an increase in U_KV at all infusion rates and had a diuretic action at a high infusion rate without producing a significant fall of BP. U_KV tended to be increased after atenolol, with essentially no change in other parameters. A new β-blocker with α-blocking action, K-351, produced a hypotension at intermediate and high infusion rates and an increase in U_NaV (low infusion rate) and U_KV (low and high rates). U_KV tended to be increased with another new β-blocker, N-696, with a fall of BP at high infusion rate. Penfluzide produced a significant decrease in BP at intermediate and high infusion rates and an increase in U_KV at all infusion rates.

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The effects of suloctidil (MY103) on the central (CNS) and peripheral nervous systems were investigated with single and consecutive administration. The general behavior in mice, awareness and motor activity were slightly depressed with the dose above 300 mg/kg, p.o. of MY 103. Soft stool was also marked in the dose above 100 mg/kg, p.o. in beagles and 1000 mg/kg, p.o. in mice. In beagles, vomiting was another syndrome with 100 and 300 mg/kg, p.o. of MY 103. Spontaneous motor activity was significantly decreased after MY 103 by p.o. administration in the dose above 100 mg/kg in mice and 300 mg/kg in rats. In sleep anesthesia studies, MY 103 and iproniazid did not potentiate the effect of a subthreshold dose of barbital, but those two drugs significantly prolonged the sleeping time of pentobarbital as chlorpromazine did. No anticonvulsive effect was observed with MY 103 in chemo- and electroshock seizure tests. MY 103 of 300 mg/kg, p.o. significantly decreased the acetic acid induced writhing number, but no analgesic activity was found in the Haffner's method in mice. In the rotarod test, MY 103 of 30-300 mg/kg, p.o. inhibited the motor coordination dose-dependently. MY 103 antagonized the m-amphetamine group toxicity. A cataleptogenic effect was observed following the relatively high dose of MY 103 by an i.p. route. This effect was antagonized by atropine. The spinal reflexes in the immobilized cat, and spontaneous rabbit EEG were not affected by MY 103. The conditioned avoidance response (CAR) was also not changed with MY 103 in rats. In the isolated phrenic-nerve diaphragm preparation, 10^-4M MY 103 irreversively inhibited the muscle twitches elicited by nerve and muscle stimulation, but suloctidil at 300 μg/kg, i.v., did not suppress the tibialis muscle twitches in vivo. In the consecutive administration study, MY 103 suppressed the CAR in rats and prolonged the thiopental-sleeping time in an administration period-related manner. These changes disappeared rapidly after drug withdrawal. Taking these evidences together, it can be concluded that MY 103 has little effect on the CNS with single administration, but the tendency to depress the CNS was observed after the repeated administration of MY 103.

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In order to understand the relationship between the cough and respiratory centers in the brain stem, we investigated the effects of antitussive drugs such as codeine, dextromethorphan, eptazocine and fominoben on respiratory movement and the cough reflex. Coughs were induced using electrical stimulation of the central cut end of the right superior laryngeal nerve in lightly anesthetized dogs. The drugs were administered intraarterially into the vertebral artery. Rate (RR), amplitude (RA) and volume (RV) of the respiration and number (NC) and amplitude (AC) of the cough reflex evoked were measured as indices. Codeine produced a decrease in RR, RV and NC at 0.3 mg and, additionally, AC at 1 mg. Dextromethorphan increased RR and RV and rather enhanced NC and AC at 0.3 mg, but the agent reduced NC and AC at 3 mg even if it increased RR and RV. Eptazocine produced decreases in RA, NC and AC at 1 mg, and, additionally, RV at 10 mg. Fominoben increased RR, RA and RV dose-dependently at 0.3-3 mg, although it depressed NC and AC at 3 mg. These findings suggest that the thresholds for the cough responses and respiratory responses to antitussive drugs are different from drug to drug and that the respiratory centers and cough center in the brain stem are affected in a different manner even qualitatively.

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