RESUMO
Proline-rich peptides from Bothrops jararaca venom (Bj-PRO) were characterized based on the capability to inhibit the somatic angiotensin-converting enzyme. The pharmacological action of these peptides resulted in the development of Captopril, one of the best examples of a target-driven drug discovery for treatment of hypertension. However, biochemical and biological properties of Bj-PROs were not completely elucidated yet, and many recent studies have suggested that their activity relies on angiotensin-converting enzyme-independent mechanisms. Here, we show that Bj-PRO-7a (Assuntos
Bothrops
, Venenos de Crotalídeos/química
, Oligopeptídeos/farmacologia
, Receptor Muscarínico M1/agonistas
, Sequência de Aminoácidos
, Animais
, Células CHO
, Sinalização do Cálcio
, Cricetinae
, Cricetulus
, Oligopeptídeos/química
, Ratos
, Receptor Muscarínico M1/biossíntese
, Proteínas Recombinantes/agonistas
, Proteínas Recombinantes/biossíntese
RESUMO
The anterior cingulate cortex (ACC) and muscarinic receptors modulate pain. This study investigates changes in the expression of muscarinic-1 and -2 receptors (M1R, M2R) in rats' ACC (cg1-rostral- and cg2-caudal) using a model of neuropathic pain by denervation, measured as autotomy score (AS) for 8 days. Changes were analysed with painful stimuli and with scopolamine into the ACC prior to this scheme. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence to determine M1R and M2R's mRNA and protein levels, respectively. Animals were divided in low, medium and high AS groups. Cg1 showed decreased mRNA levels for both M1R and M2R in the low AS group, as opposed to an increased expression in the medium and high AS groups. Both receptors correlated positively with AS in these groups. In the scopolamine-treated animals there was an increase in mRNA levels for both receptors in cg1, whereas in cg2, mRNA levels of M1R decreased in all the AS and scopolamine groups. The increased M2R mRNA in cg2 correlated with AS in the low, medium and high AS groups whereas all the scopolamine groups showed an increase. Immunoreactivity of the M2R in cg1 decreased in the medium AS group in comparison to controls but scopolamine treatment produced an increase in the medium scopolamine AS group compared to the medium AS group. The M1R in cg1 and both receptors in cg2 showed no immunoreactivity changes. These results highlight the role of the M2R in cg1 related to the degree of autotomy.
Assuntos
Modelos Animais de Doenças , Giro do Cíngulo/metabolismo , Antagonistas Muscarínicos/farmacologia , Dor/metabolismo , Doenças do Sistema Nervoso Periférico/metabolismo , Receptor Muscarínico M1/biossíntese , Receptor Muscarínico M2/biossíntese , Escopolamina/farmacologia , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Giro do Cíngulo/efeitos dos fármacos , Masculino , Dor/tratamento farmacológico , Medição da Dor/métodos , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , RNA Mensageiro/biossíntese , Ratos , Ratos Wistar , Receptor Muscarínico M1/antagonistas & inibidores , Receptor Muscarínico M1/genética , Receptor Muscarínico M2/antagonistas & inibidores , Receptor Muscarínico M2/genéticaRESUMO
Protein kinase C (PKC) plays a key role in cellular events including proliferation, survival and differentiation. Our previous study showed the effect of phorbol 12-myristate 13-acetate (PMA), a PKC activator, inducing a decrease in retinal cells proliferation. This effect was mediated by muscarinic type 1 receptors (M1) activation and brain derived neurotrophic factor (BDNF) treatment also induced a decrease in cell proliferation. Based on these results we analyzed the expression of either M1 receptors or BDNF following PMA treatment of retinal cell cultures. Our data demonstrated that PMA induced a decrease in both protein expressions after 48 h in culture. However, after 45 min, PMA induced a transient increase in BDNF expression and a decrease in M1 receptors expression. Analyzing the expression of M1 receptors and BDNF during the postnatal development in vivo, we observed a decrease in both proteins. Taken together our results suggest the involvement of PKC in the control of M1 expression in retinal cells.