Nitric oxide of the supraoptic nucleus influences the salivary secretion, sodium renal excretion, urinary volume and arterial blood pressure induced by pilocarpine.
Male Holtzman rats weighting 200-250 g were anesthetized with zoletil 50 mg/Kg (tiletamine chloridrate 125.0 mg and zolazepan chloridrate 125.0 mg) into quadriceps muscle and stainless steel cannulas were implanted into their supraoptic nucleus (SON). We investigated the effects of the injection into the supraoptic nucleus (SON) of FK 409, a nitric oxide donor, and NW-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor (NOS), on the salivary secretion, arterial blood pressure, sodium excretion and urinary volume induced by pilocarpine, which was injected into SON. The drugs were injected in 0.5 microl volume over 30-60 s. Controls was injected with a similar volume of 0.15 M NaCl. FK 409 and L-NAME were injected at doses of 20 microg/0.5 microl and 40 microg/0.5 microl respectively. The amount of saliva secretion was studied over a five-minute period after injection of pilocarpine into SON. Injection of pilocarpine (10, 20, 40, 80, 160 microg/microl) into SON produced a dose-dependent increase in salivary secretion. L-NAME was injected into SON prior to the injection of pilocarpine into SON, producing an increase in salivary secretion due to the effect of pilocarpine. FK 409 injected into SON attenuating the increase in salivary secretion induced by pilocarpine. Mean arterial pressure (MAP) increase after injections of pilocarpine into the SON. L-NAME injected into the SON prior to injection of pilocarpine into SON increased the MAP. FK 409 injected into the SON prior to pilocarpine attenuated the effect of pilocarpine on MAP. Pilocarpine (0.5 micromol/0.5 microl) injected into the SON induced an increase in sodium and urinary excretion. L-NAME injected prior to pilocarpine into the SON increased the urinary sodium excretion and urinary volume induced by pilocarpine. FK 409 injected prior to pilocarpine into the SON decreased the sodium excretion and urinary volume induced by pilocarpine. All these roles of pilocarpine depend on the release of nitric oxide into the SON. In summary the present results show: a) SON is involved in pilocarpine-induced salivation; b) that mechanism involves increase in MAP, sodium excretion and urinary volume.
Saad
Wilson Abrão
WA
Department of Physiology and Pathology School of Dentistry, Paulista State University, UNESP Araraquara, SP, Brazil. silvana@foar.unesp.br
Gutierrez
Laura Izabel
LI
Guarda
Ismael Francisco Motta Siqueira
IF
Camargo
Luis Antonio de Arruda
LA
dos Santos
Talmir Augusto Faria Brisola
TA
Saad
William Abrão
WA
Simões
Sylvio
S
Guarda
Renata Saad
RS
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000378:metabolism; D008297:Male; D018721:Muscarinic Agonists / Q000378:metabolism* / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000378:metabolism; D009318:Natriuresis / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism; D009574:Nitro Compounds / Q000378:metabolism; D010862:Pilocarpine / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012472:Salivation / Q000502:physiology*; D013495:Supraoptic Nucleus / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*
D004791:Enzyme Inhibitors; D018721:Muscarinic Agonists; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D010862:Pilocarpine; D009569:Nitric Oxide; C061872:FK 409; D019331:NG-Nitroarginine Methyl Ester