PubMed · 5436619
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R Haley, S Shropshire, O N Markand, J R Crout, N M Kaplan, E H Eigenbrodt. 1970. Clinico-pathologic conference.. https://pubmed.ncbi.nlm.nih.gov/5436619/
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1. Amperometric recordings were made from individual phaeochromocytoma (PC12) cells using carbon fibre microelectrodes to investigate the effects of chronic hypoxia (10% O2) on the secretory responses evoked by acute hypoxia. 2. Exposure to chronic hypoxia for 21-26 h increased the frequency of exocytotic events evoked in response to acute hypoxia (PO2 ca 10-60 mmHg). 3. Chronic hypoxia increased the value of Q1/3, determined by the integration of amperometric events, indicating an increase in quantal size: this reflects either an increase in vesicular dimensions or vesicular catecholamine concentration. 4. Exocytotic frequency evoked by bath application of tetraethylammonium (1-10 mM) was significantly enhanced following chronic hypoxia. 5. In both control and chronically hypoxic PC12 cells, exocytosis in response to acute hypoxia was completely abolished in Ca2+-free solutions. Cd2+ (200 microM) completely inhibited exocytosis from control cells, but left a significant residual release in chronically hypoxic PC12 cells. 6. The Cd2+-resistant release evoked by acute hypoxia in chronically hypoxic PC12 cells was inhibited by inorganic ions (0.01-10 mM) in a potency order of La3+ > Gd3+ > Zn2+. Ni2+ (10 mM) was without effect. 7. Our results suggest that chronic hypoxia enhances the secretory response of PC12 cells in part by increasing the depolarization mediated by an oxygen-sensitive K+ channel. In addition, acute hypoxia activates a Cd2+-resistant Ca2+ influx pathway in chronically hypoxic PC12 cells.
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BACKGROUND: The use of minimally invasive techniques in the surgical treatment of pheochromocytoma is controversial because of possible intraoperative excessive hormone release resulting in cardiovascular instabilities. METHODS: Laparoscopic adrenalectomy was performed in nine patients with a total of 10 pheochromocytomas. Conversion was required in two cases. The relevant data were prospectively documented and compared with a historical group of nine patients who had undergone conventional transabdominal adrenalectomy for unilateral pheochromocytoma. RESULTS: The laparoscopic operations lasted significantly longer than the conventional procedures (median 243 min vs. 100 min, p < 0.01). Intraoperative cardiovascular instabilities (tachycardia, hypertension) occurred in seven laparoscopically and eight conventionally treated patients. All were easily controlled. Blood transfusions were necessary in four patients in the conventional and one patient in the laparoscopic group. Postoperative hospital stay and duration of analgetic treatment were significantly shorter after laparoscopic adrenalectomy. CONCLUSIONS: Laparoscopic adrenalectomy is a safe procedure for patients with pheochromocytoma.