Role of the CNS in the control of the water economy of the toad Bufo arenarum Hensel - II. Adrenergic control of water uptake across the skin
1. Subcutaneous administration of a sympathoplexic drug, guanethidine, induced intensive uptake of water across the skin of the toad, Bufo arenarum, maintained in fresh water, even after complete removal of the ADH producing system. Guanethidine had no effect in the midbrain lesioned toad. No signif...
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1982
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01741578_v146_n1_p101_Segura http://hdl.handle.net/20.500.12110/paper_01741578_v146_n1_p101_Segura |
| Aporte de: |
| Sumario: | 1. Subcutaneous administration of a sympathoplexic drug, guanethidine, induced intensive uptake of water across the skin of the toad, Bufo arenarum, maintained in fresh water, even after complete removal of the ADH producing system. Guanethidine had no effect in the midbrain lesioned toad. No significant changes in urine production were detected. 2. Phenoxybenzamine, an alpha-adrenergic blocker, closely reproduced the guanethidine effect. Conversely, the alpha-agonist metaraminol induced a decrease in water uptake with associated oliguria. 3. Microinjection of phenoxybenzamine into the brain increased water uptake when applied to the midbrain tegmentum and decreased urine production when applied to the forebrain. 4. The data show that an adrenergic mechanism is associated with the control of water uptake through toad skin. This mechanism is at least in part dependent on the midbrain tegmentum and not on the diencephalic ADH production system. The main function of this adrenergic control is probably to prevent excessive uptake of water in the intact animal during long sojourns in fresh water. It might also serve to prevent a leaching-out of electrolytes. © 1982 Springer-Verlag. |
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