Antidiuretic responses to osmotic cutaneous stimulation in the toad Bufo arenarum. A possible adaptative control mechanism for urine production

PETRIELLA, S.; JUAN C. REBOREDA; OTERO, M.; SEGURA, E. T.

Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology

Año: 1989 vol. 159 p. 91 - 95

0174-1578

Osmotic stimulation of the skin of the toad Bufo arenarum with isotonic (115 mM) or hypertonic (400 mM) NaCI solutions produced a marked and reversible antidiuresis within 5 min. No changes in plasma osmolarity were detecte in the course of this response. Hypophysectomized animals exhibited a lower and delayed antidiuresis when exposed to a hypertonic environment (400 mM NaC1). This antidiuretic response was drastically reduced in normal toads after ten consecutive days of administrationof the sympatoplexic guanethidine. The existence of a feed-forward control of urineproduction initiated by cutaneous osmotic sensors and involving an adrenergic component is proposed.