Inhibition of the morphogenesis of the otoliths in the chick embryo in the presence of carbonic anhydrase inhibitors

Riassunto Vengono studiati gli effetti sullo sviluppo del labirinto membranoso dell'embrione di pollo di alcuni inibitori della anidrasi carbonica (acetazolamide, dichlorofenamide, etossizolamide, neptazano). L'azione di tali sostanze si manifesta con una elettiva inibizione della morfogenesi degli otoconi.     

Uptake of metabolic CO2 by the otoliths of the chick embryo

Riassunto Viene condotto uno studio sulla utilizzazione dell' NaHC¹⁴O₃ e C¹⁴H₃C¹⁴OC¹⁴OOH nel processo di calcificazione degli otoliti dell'embrione di pollo. I risultati delle indagini condotte hanno messo in evidenza la prevalente utilizzazione della CO₂ metabolica in tale processo.     

The effect of 4,5-dichlor-1,3-benzendisulfonamide and of 4,5-dichlor-1,3-benzendisulfonylaniline on the morphogenesis of the otoliths in the chick embryo

Riassunto Inoculando in embrioni di pollo di 4 giorni di sviluppo un inibitore dell'anidrasi carbonica (4, 5-Dicloro-1, 3-Benzendisolfonamide) o un suo derivato inattivo nel quale un atomo di idrogeno dei 2 gruppi SO₂NH₂ è sostituito da radicali fenilici (4, 5-Dicloro-1, 3-Benzendisolfonilanilina), si nota una inibizione selettiva della morfogenesi degli otoliti in presenza di 4, 5-Dicloro-1, 3-Benzendisolfonamide.     

On the presence of mucopolysaccharide material in the labyrinthine epithelium of chick embryo in the first moments of morphogenesis

Riassunto Viene segnalata la presenza di materiale mucopolisaccaridico neutro in alcune cellule dell'epitelio del labirinto membranoso dell'embrione di pollo durante i primi periodi dello sviluppo. Viene avanzata l'ipotesi che tale materiale possa essere connesso con la genesi delle cupole ampollari e delle membrane otolitiche.      

Increase in the oxygen available to the cerebral cortex after the administration of carbonic anhydrase inhibitors]

Oxygen tension (pO2) in cerebral cortex was measured by polarographic method in unanesthetized rabbits. Intravenous administration (25 mg/kg) of carbonic anhydrase inhibitors (acetazolamide, methazolamide, dichlorphenamide, sulthiame) induced an early important rise of cortical p O2, which is not dependent on increase of p O2 and p CO2 and decrease of pH in arterial blood. High dosage of acetazolamide (250 mg/kg) produced the same effect and did not suppress the increase of cortical p O2 under air-CO2 inhalation. This result suggests that CO2 might act specifically upon cerebral vessels.     

Effects of parathyroid hormone and calcitonin on carbonic anhydrase location in osteoclasts of cultured embryonic chick bone

The ultrastructural location of carbonic anhydrase has been examined in osteoclasts of cultured embryonic chick metatarsi. In untreated cultures and in those to which parathyroid hormone (PTH) was added, the enzyme was found in close association with the plasma membrane of the ruffled border. After brief calcitonin treatment (10 min) the ruffled border disappeared and the association of carbonic anhydrase with the plasma membrane was diminished. The results indicate that the hormones employed act directly on embryonic bone to alter osteoclast structure and the intracellular location of carbonic anhydrase.     

Effects of parathyroid hormone and calcitonin on carbonic anhydrase location in osteoclasts of cultured embryonic chick bone

Summary The ultrastructural location of carbonic anhydrase has been examined in osteoclasts of cultured embryonic chick metatarsi. In untreated cultures and in those to which parathyroid hormone (PTH) was added, the enzyme was found in close association with the plasma membrane of the ruffled border. After brief calcitonin treatment (10 min) the ruffled border disappeared and the association of carbonic anhydrase with the plasma membrane was diminished. The results indicate that the hormones employed act directly on embryonic bone to alter osteoclast structure and the intracellular location of carbonic anhydrase.Acknowledgments. This work was supported by NIH grants DE04345 and AM20374. Dr Cao was a visiting scientist from the Department of Biology, East China Normal University, Shanghai, The Peoples Republic of China. We thank Kathryn Majarwitz for assisting with the morphometric analysis. The PTH was provided by the National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases of the National Institutes of Health, US Department of Health and Human Services.     

Histochemical localization of carbonic anhydrase in fowl proventriculus

Summary The carbonic anhydrase activity in fowl proventriculus was studied by the histochemical method of Hansson. The activity was observed in the mucose membrane cells and in proventricular gland cells. These results, about which there is disagreement in the literature, are discussed in the text.