Interaction between paraventricular nucleus and medial septal area on the renal effects induced by adrenaline.
The aim of the present study was to analyze the role of alpha1, alpha2-adrenoceptors, and the effects of losartan and PD123319 (selective ligands of the AT1 and AT2 angiotensin receptors, respectively) injected into the paraventricular nucleus (PVN) on the diuresis, natriuresis, and kaliuresis induced by administration of adrenaline into the medial septal area (MSA). Male Holtzman rats with a stainless steel cannula implanted into the MSA and bilaterally into the PVN were used. The administration of adrenaline into the MSA increased in a dose-dependent manner the urine, sodium, and potassium excretions. The previous administration of prazosin (an alpha1-adrenoceptor antagonist) injected into the PVN abolished the above effects of adrenaline, whereas yohimbine (an alpha2-adrenoceptor antagonist) doesn't affect the diuresis, natriuresis, and kaliuresis induced by adrenaline. Pretreatment with losartan into the PVN decreased in a dose-dependent manner the urine, sodium, and potassium excretions induced by MSA administration of adrenaline (50 ng), while PVN PD123319 was without effect. These results indicate that urinary and electrolyte excretion effects induced by adrenaline into the MSA are mediated primarily by PVN AT1 receptors. However, the doses of losartan were more effective when combined with the doses of PD123319 than given alone, suggesting that the urinary, natriuretic, and kaliuretic effects of MSA adrenaline may involve activation of multiple angiotensin II receptors subtypes into the PVN.
de Arruda Camargo
Luiz Antonio
LA
Department of Physiology, School of Dentistry, Paulista State University, UNESP. Rua Humaitá, 1680, Unitau Taubaté SP. Uniara 14801-903, SP Araraquara, SP Brazil. silvana@foar.unesp.br
Saad
Wilson Abrão
WA
de Souza Villa
Patrícia
P
D000322:Adrenergic Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D019808:Losartan / Q000494:pharmacology; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology* / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology; D012686:Septal Nuclei / Q000166:cytology* / Q000502:physiology*; D014556:Urine
D000322:Adrenergic Agonists; D000317:Adrenergic alpha-Antagonists; D000959:Antihypertensive Agents; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2; D019808:Losartan; D011224:Prazosin; D004837:Epinephrine