The effects of antidepressants and pilocarpine on rat parotid glands: an immunohistochemical study

OBJECTIVES: To evaluate the effects of antidepressants and pilocarpine on the quantity of myoepithelial cells and on the proliferation index of the epithelial cells of rat parotid glands. INTRODUCTION: Hyposalivation, xerostomia, and alterations in saliva composition are important clinical side effects related to the use of antidepressants. METHODS: Ninety male Wistar rats were allocated to nine groups. The control groups received saline for 30 (group C30) or 60 days (group C60) or pilocarpine for 60 days (group Pilo). The experimental groups were administered fluoxetine (group F30) or venlafaxine for 30 days (group V30); fluoxetine (group FS60) or venlafaxine (group VS60) with saline for 60 days; or fluoxetine (group FP60) or venlafaxine (group VP60) with pilocarpine for 60 days. Parotid gland specimens were processed, and the immunohistochemical expression of calponin and proliferating cell nuclear anti-antigen on the myoepithelial and parenchymal cells, respectively, was evaluated. Analysis of variance (ANOVA), Tukey HSD and Games-Howell tests were applied to detect differences among groups (p<0.05). RESULTS: Compared with the controls, chronic exposure to antidepressants was associated with an increase in the number of positively stained cells for calponin. In addition, venlafaxine administration for 30 days was associated with an increase in the number of positively stained cells for proliferating cell nuclear anti-antigen. Fluoxetine and pilocarpine (group FP60) induced a significant decrease in the number of positively stained cells for calponin compared with all other groups. CONCLUSIONS: The number of positively stained cells for calponin increased after chronic administration of antidepressants. The proliferation index of the epithelial cells of rat parotid glands was not altered by the use of antidepressants for 60 days.

Epidermal growth factor receptors, testosterone levels and parotid gland changes in rats infected with Trypanosoma cruzi

It has been demonstrated that parotid glands of rats infected with Trypanosoma cruzi present severe histological alterations; changes include reduction in density and volume of the acini and duct systems and an increase in connective tissue. We evaluated the association between morphological changes in parotid glands, circulating testosterone levels and epidermal growth factor receptor (EGF-R) expression in experimental Chagas disease in rats. Animals at 18 days of infection (acute phase) showed a significant decrease in body weight, serum testosterone levels and EGF-R expression in the parotid gland compared with a control group. Since decreases in body weight could lead to a reduction in circulating testosterone concentration, we believe that the reduction in EGF-R expression in parotid glands of infected rats is due to alterations in testosterone levels and atrophy of parotid glands is caused by changes in EGF-R expression. Additionally, at 50 days (chronic phase) of infection parotid glands showed a normal histological aspect likely due to the normalization of the body weight. These findings suggest that the testosterone-EGF-R axis is involved in the histological changes.

Alteration of Expression of Ca(2+) Signaling Proteins and Adaptation of Ca(2+) Signaling in SERCA2(+/-) Mouse Parotid Acini

PURPOSE: The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA), encoded by ATP2A2, is an essential component for G-protein coupled receptor (GPCR)-dependent Ca(2+) signaling. However, whether the changes in Ca(2+) signaling and Ca(2+) signaling proteins in parotid acinar cells are affected by a partial loss of SERCA2 are not known. MATERIALS AND METHODS: In SERCA2(+/-) mouse parotid gland acinar cells, Ca(2+) signaling, expression levels of Ca(2+) signaling proteins, and amylase secretion were investigated. RESULTS: SERCA2(+/-) mice showed decreased SERCA2 expression and an upregulation of the plasma membrane Ca(2+) ATPase. A partial loss of SERCA2 changed the expression level of 1, 4, 5-tris-inositolphosphate receptors (IP(3)Rs), but the localization and activities of IP3Rs were not altered. In SERCA2(+/-) mice, muscarinic stimulation resulted in greater amylase release, and the expression of synaptotagmin was increased compared to wild type mice. CONCLUSION: These results suggest that a partial loss of SERCA2 affects the expression and activity of Ca(2+) signaling proteins in the parotid gland acini, however, overall Ca(2+) signaling is unchanged.

Interaction of l - arginine / nitric oxide system with lead acetate on secretion of amylase from isloated rat parotid glands.

In the present study the effects of lead acetate and/or L-Arginine as a nitric oxide precursor and L-NAME as a nitric oxide synthase inhibitor on the amylase secretion of rat parotid gland lobules were investigated. Lead acetate in doses of 3, 30 and 300 micro M significantly [P<0.01] caused a dose-dependent reduction in isoproterenol-stimulated or non-stimulated amylase secretion. When secretion of saliva was not stimulated by beta-adrenergic agonist, L-Arginine [100 micro M] significantly [P<0.01] reduced amylase output. L-NAME [100 micro M] alone had no significant effect on amylase output but when used with lead acetate prevented [P<0.01] from lead-induced reduction of amylase output. Both L-NAME [100 micro M] and L-Arginine [100 micro M]] when used alone reduced isoproterenol-stimulated amylase output. Concurrent administration of lead acetate [300 micro M]] with either L-Arginine [100 micro M] or L-NAME [100 micro M] showed a marked positive interaction in reducing the isoproterenol-stimulated secretion of amylase. These findings suggest that nitric oxide plays a role in secretion of amylase from parotid. Different affinity of lead acetate to interact with different nitric oxide synthases might be a reason for different effects on parotid amylase secretion observed in the presence or absence of secretion stimulant

Fluid and amylase secretion by perfused parotid gland: physio-morphological approach

Whole gland perfusion technique was applied to rat parotid glands to assess whether amylase affects fluid secretion. Control perfusion without any secretagogue evoked no spontaneous secretion. Carbachol (CCh 1 microM) induced both amylase and fluid secretion with distinctive kinetics. Fluid secretion occurred constantly around 60 microL/g-min, whereas amylase secretion exhibited an initial peak, followed by a rapid decrease to reach a plateau. Isoproterenol (Isop 1 microM) alone did not induce fluid secretion although it evoked amylase secretion as measured in isolated perfused acini. Addition of Isop during CCh stimulation evoked a rapid and large rise in amylase secretion accompanied by small increase in oxygen consumption. Morphological observations carried out by HR SEM and TEM revealed exocytotic profiles following Isop stimulation. CCh stimulation alone seldom showed exocytotic profiles, suggesting a low incidence of amylase secretion during copious fluid secretion. Combined stimulation of CCh and Isop induced both vacuolation and exocytosis along intercellular canaliculi. These findings suggest that control of salivary fluid secretion is independent of the amylase secretion system induced by CCh and/or Isop.

Parótida bovina: purificaçäo e caracterizaçäo da fosfatase ácida de baixo peso molecular / Bovine kidney: purification and characterization of acid phosphatase of low molecular weight

A fosfatase ácida de BPM da parótida bovina foi purificada 1.800 vezes até a homogeneidade, com rendimento de 8 por cento, através de um procedimento envolvendo fracionamento com sulfato de amônio, tratamento ácido e cromatografia de troca iônica em SP-Sephadex com eluiçäo por íon-afinidade. Os critérios de pureza utilizados foram a A.E., PAGE, SDS-PAGE, filtraçäo em gel (Superdex HR 70) e análise da composiçäo de aminoácidos. A enzima purificada (A.E. de 100 µmol min-1 mg-1) é composta por uma cadeia polipeptídica simples e possui Mr de 13,6 e 19 kDa, como determinado através da filtraçäo em gel e SDS-PAGE, respectivamente. A composiçäo parcial de aminoácidos (Cys e Trp näo foram determinados) foi obtida após a hidrólise ácida da proteína purificada seguida da análise dos resíduos de aminoácidos e evidenciou a existência de, pelo menos, 151 resíduos de aminoácidos...