Relationship between Ca2+ and cAMP as second messengers in ACTH-induced cortisol production in bovine adrenal fasciculata cells

In adrenal fasciculata cells stimulated by ACTH, Ca2+ and cAMP play indispensable roles as second messengers in cortisol production. However, whether their second messengers cooperatively or independently participate in steroid production remains unclear. We focused on the roles of Ca2+ and cAMP in cortisol production in bovine adrenal fasciculata cells stimulated by ACTH for a relatively short period (1 h). Incubation of the cells with 100 pM ACTH in Ca2+-containing (normal) medium for 1 h increased cortisol production without affecting cAMP content. In contrast, treatment of the cells with the peptide at a higher concentration (1 nM) significantly augmented both cortisol production and cAMP content. However, ACTH did not increase either of them in the Ca2+-free medium. ACTH rapidly increased the intracellular free Ca2+ concentration ([Ca2+]i) in the normal medium, but did not influence [Ca2+]i in the Ca2+-free medium, indicating that ACTH caused Ca2+ influx into the cells. ACTH-induced Ca2+ influx and cortisol production were suppressed by a voltage-sensitive L-type Ca2+ channel blocker but not by a T-type, N-type, or P-type Ca2+ channel blocker. In contrast, dibutyryl cAMP, a cell-permeable cAMP analog, greatly enhanced cortisol production in the normal or Ca2+-free medium and slowly caused Ca2+ influx into the cells. These results strongly suggest that Ca2+, as a second messenger, is more critical than cAMP for cortisol production. However, both second messengers jointly participate in the production in adrenal fasciculata cells stimulated by ACTH.

Effects of ginseng saponins on responses induced by various receptor stimuli

We investigated the effects of four ginseng saponins, ginsenoside-Rb1, -Rg2, -Rg3 and -Ro, on the responses induced by receptor stimulation of various stimuli. Ginsenoside-Rg2 (1-100 microM) reduced the secretions of catecholamines from bovine adrenal chromaffin cells stimulated by acetylcholine and gamma-aminobutyric acid but not by angiotensin II, bradykinin, histamine and neurotensin. In guinea-pig, the ginsenoside also diminished the nicotine-induced secretion of catecholamines from the adrenal chromaffin cells, but it did not affect the muscarine- and the histamine-induced ileum contractions. On the other hand, ginsenoside-Rg3 (1-100 microM) reduced not only the acetylcholine-, the gamma-aminobutyric acid- and the neurotensin-induced secretions but also, at a higher concentration (100 microM), the angiotensin II-, the bradykinin- and the histamine-induced secretions from the bovine chromaffin cells. Furthermore, the saponin (3-100 microM) significantly inhibited the muscarine- and the histamine-induced ileum contractions of the guinea-pig. Ginsenoside-Rb1 and -Ro had no marked effect on their responses. These results strongly suggest that ginsenoside-Rg2 is a potent selective blocker of nicotinic acetylcholine and gamma-aminobutyric acid receptors (ionotropic receptors) and ginsenoside-Rg3 is not only a blocker of ionotropic receptors but also an antagonist of muscarinic or histamine receptors.

[Informed consent in anesthesia]

Informed consent is required for not only operative procedures but also anesthesia. One hundred and sixty-two patients, including those in a control group, were interviewed between the 3rd and 10th days after operations. An information sheet describes the anesthetic management and complications (possibilities of teeth damage, hoarseness and sore throat) in a simple style. This survey showed that those who had received the information sheet before operation showed significantly deeper understanding of anesthesia (56.2%) compared with those who had not received the information sheet (40.3%) (P < 0.05). The information sheet did not cause or increase anxiety about anesthesia. Those who had anxiety about anesthesia before the operation needed detailed printed information (63.8%) compared with those without anxiety (36.6%) (P < 0.01). An information sheet describing the anesthetic management and complications is useful for obtaining informed consent.

[Coronary artery spasm under general and epidural anesthesia]

A 66-year-old man without history of angina pectoris was scheduled for subtotal gastrectomy under epidural anesthesia supplemented with nitrous oxide and isoflurane. ECG showed an elevation of ST segment after hypotension. It passed into Wenckebach A-V block and complete A-V block. But an elevation of ST segment was relieved by raising blood pressure and it became sinus rhythm. Serum enzymes (CPK-MB, GOT and LDH) were normal after operation. It is suspected that coronary spasm was induced by hypotension and vagal stimulation under inadequate level of anesthesia, though we could not prove this arteriographically.

[Two cases of pulmonary edema during and after cesarean section]

Pulmonary edema occurred during and after Cesarean section under general anesthesia in two pregnant women. They had no preoperative complication. After delivery, anesthesia was maintained with 66% N2O in oxygen and intravenous injection of pentazocine and diazepam. At the same time, 0.2 mg of methylergometrin was injected intramuscularly and 2,000 micrograms of prostaglandin F2 alpha was injected to the muscle of the uterus in order to induce uterine contraction. In one case, SpO2 dropped and airway pressure increased immediately after the administration. In another case, chest rale was auscultated on postoperative round at 2 hours after operation. The cases suggest that pulmonary edema was caused by a large quantity of oxytocics, which increased volume load on systemic circulation.