Learn More
Para-aminohippuric acid (PAH, 0.2 and 1 mmol l(-)(1)) had no effect on the basal fluid secretion rate (FSR) of isolated Malpighian tubules of Drosophila melanogaster Meig. and did not affect stimulation of the FSR induced by adenosine 3',5'-monophosphate (cAMP). Phenol Red (phenolsulphonphthalein, PSP; 0.5 and 1 mmol l(-)(1)) slowed the FSR and abolished(More)
External application of the 3′,5′-cyclic monophosphates of inosine, cytidine, uridine and thymidine stimulated the fluid secretion rate (FSR) of Malpighian tubules isolated from Drosophila melanogaster. The evidence suggested that the cyclic nucleotides acted intracellularly in some capacity. Receptors of the ‘purinergic’ type appeared not to be major(More)
The gross microscopical anatomy of the crayfish antennal gland has been well and repeatedly characterized (Marchal, 1892; Peters, 1925; Maluf, 1939). Examination of the anatomy of the organ has yielded little information elucidating its basic functional mechanism. Since the work of Schlieper & Herrmann (1930) it has been known that the crayfish excretes a(More)
Single glomerulus filtration rate in Eptatretus stouti averaged 20.3+/-2.13 (S.E.M.) nl min(-1). Single glomerulus glomerular filtration rate (GFR) could be correlated with arterial pressure when arterial pressure exceeded about 4 cm H2O. Glomerular filtration was affected by postglomerular resistance brought about by alteration of the volume of urinary(More)
The evidence presently available supports a ' filtration '-reabsorption hypothesis for the mechanism underlying urine formation by the antennal gland of the crayfish. This evidence has been summarized most recently by Schmidt-Nielsen & Laws (1963) and by the writer (1963). In a previous paper (Riegel, 1963) the results of measurements of chloride(More)
Studies of ion concentrations and osmotic pressures in the crayfish antennal gland have revealed a major discrepancy. The osmotic pressure of the urine in the tubular portion of the gland falls (Riegel, 1963). However, the sodium and potassium concentrations measured there exceed the osmotic pressure (Riegel, 1965). To complicate the situation further,(More)
Single renal corpuscles of hagfish were perfused with a Ringer solution containing Ficoll 70 to simulate the colloid osmotic pressure of hagfish plasma. Simultaneous measurements were made of single glomerulus filtration rate (SGFR), perfusion pressure and the pressure in a vessel of the renal vasculature. The results confirm that SGFR is independent of(More)
Hydrostatic pressures in the renal vasculature of hagfish have been studied. Estimates of the blood colloid osmotic pressure (COP) have been made. In blood vessels supplying the renal corpuscles, the average hydrostatic pressure is about 1 kPa. The average hydrostatic pressure falls to a value of 0.04 kPa within the postcardinal vein efferent to the renal(More)
In the course of investigations of the formation of urine by the antennal gland of the crayfish it was discovered that this process involved the secretion of formed bodies. The appearance and partial chemical analyses of the formed bodies of the crayfish are reported on elsewhere (Riegel, 1966). In the present report the lipid character of the walls of the(More)
Numerous investigators have remarked upon the secretory appearance of the labyrinth and coelomosac of the crayfish antennal gland (e.g. Marchal, 1892; Peters, 1935; Maluf, 1939). It is readily observed in stained sections that vesicles are formed at the lumenad borders of the labyrinth cells. Furthermore, the cells of the coelomosac appear to be filled with(More)