Effect of dopamine receptor blockade on the renal excretory response to acute volume expansion (AVE) in conscious Brattleboro rats.
All the studies were performed on chronically cannulated, conscious Brattleboro rats, housed in metabolic cages under standard conditions. The renal excretory indices: diuresis (V), sodium (UNa.V), potassium (UK.V), chloride (UCl.V) and osmotic (Uosm.V) excretion were measured under the following experimental protocol: (1) controls, (2) 2% volume expansion (AVE)-0.9% NaCl i.v. for 2 min, (3) Dopamine (DA) receptor antagonist Flupentixol (FLU) 0.5 mg.kg-1 i.v., and (4) AVE 10 min after i.v. application of FLU. All the indices studied, given as cumulative curves, showed a firm linearity with time during the whole experimental period (5 h) in groups 1 and 2 (p < 0.05), while such a relationship was not found significantly in groups 3 and 4. AVE quickly, strongly and significantly (p < 0.01) increased V and especially UNa.V, UCl.V and Uosm.V. Pretreatment with FLU potently suppressed the effect of AVE on the renal excretion. FLU alone decreased almost equally V and saliuresis.


CONCLUSIONS
the DA antagonist FLU blocks the diuretic and saliuretic response to AVE probably by affecting tubular processes.
Tzaneva
N
N
Department of Physiology, Medical Faculty, Sofia, Bulgaria.
Belova
N
N
Kirkova
L
L
Piryova
B
B
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001810:Blood Volume / Q000502:physiology*; D002712:Chlorides / Q000652:urine; D018492:Dopamine Antagonists / Q000494:pharmacology*; D005475:Flupenthixol / Q000494:pharmacology; D006339:Heart Rate / Q000502:physiology; D007668:Kidney / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D011188:Potassium / Q000652:urine; D051381:Rats; D011910:Rats, Brattleboro; D012964:Sodium / Q000652:urine; D014563:Urodynamics / Q000502:physiology
D002712:Chlorides; D018492:Dopamine Antagonists; D012964:Sodium; D005475:Flupenthixol; D011188:Potassium