ABSTRACT
Aim To investigate the effect on antagonism of benthiactzine and atropine against the function of muscarinic acetylcholine receptors by desensitization of nicotinic acetylcholine receptors. Methods The whole cell recording configuration of patch-clamp technique was used and the cell model was rat SCG neurons. To identify antagonists' antimuscarinic effect, mAchRs mediated IM-inhibition was measured and nicotine and oxotremorine were used. Results After de sensitization of nAChRs,the antimuscarinic effect ofboth benthiactzine and atropine decreased compared to the normal condition. The decreased antimuscarinic effect of benthiactzine was weaker than that of atro-pine. The antimuscarinic effect of both benthiactzine and atropine recovered gradually with the recovery of nAChRs from desensitization. Conclusion Desensiti-zation of nAChRs weakens the antagonists' antimuscarinic effect.
ABSTRACT
AIM To study the effect of ATP sensitive potassium channel(K ATP ) opener pinacidil on the current induced by nicotine in cultured rat superior cervical ganglia. METHOD Whole cell patch clamp technique. RESULTS Pinacidil inhibited nicotine induced current when in higher dose(100 ?mol?L -1 ), but had no effect on the desensitization of nicotinic receptors. K ATP antagonist glibenclamide didn't influence the inhibitory effect of pinacidil on nicotinic current. CONCLUSION Pinacidil had an inhibitory effect on nicotine induced current in rat superior cervical ganglia and this effect wasn't mediated by K ATP .
ABSTRACT
Nerve growth factor (NGF) can promote the outgrowth of neurites of the target ganglia. In order to further explore the relationship between this effect and the synthesis of RNA and DNA in the neurons, an autoradiography of 3~H-uridine and 3~H-thymidine was used. Superior cervical ganglia (SCG) from newborn rats were cultivated by Maximow's double coverslip method. All cultures were divided to one group of cultures a crude preparation of NGF was added to the medium and another group without NGF served as control. Before tissue culture was stopped, the. covership cultures were transferred to thelabeling-medium and incubated, and then they were fixed, and cut into serial sections and subjected to autoradiographie processes. The results show that the percentage and the level of grains of neurons labeled by 3~H-uridine in the NGF group are higher than that of control. Moreover, before the growth rate of neurites reaches a peak, the level of grains of neurons labeled by 3~H-uridine in the NGF group is obviously increased. The evidence suggests that NGF can promote the synthesis of RNA in neurons of SCG, which has a direct bearing on the quick outgrowth of neurites. In the experiments with 3~H-thymidine incorporation, that the NGF may promote the synthesis of DNA in some neurons of the third day SCG in vitro was also observed.
ABSTRACT
The superior cervical ganglia (SCG) were dissected from neonatal rats.Dissoci-ated cell cultures were grown in Eagle's MEM supplemented with 20% calf serumwhich contain nerve growth factor (NGF).The cultures were divided into two groups:laser irradiation group and control.The former was exposed to lower dose of Helium-Neon laser (power:4 milliwatt)5 minutes every two hours.Two groups cultured for 20,22,24 and 28 hoursrespectively.Then the length of neurites of neurons were measured.At 22 hours,RNA and DNA synthesis of neurons labeled by ~3H-uridine and ~3H-thymidine wereobserved.The results showed that lower dose of Helium-Neon laser irradiation not onlypromotes growth of neurite but also enhances RNA synthesis of neurons in culture.However DNA synthesis in neurons does not promote in this experiment.
ABSTRACT
Objective To detect the location of histamine in peripheral sympathetic nerves of guinea pig. Methods Histidine decarboxylase mRNA was detected using in situ hybridization histochemistry with specific oligonucleotide probe,while histamine and tyrosine hydroxylase were detected using double labeled immunohistochemistry with anti-histamine antibody and anti-tyrosine hydroxylase antibody in the superior cervical ganglia of guinea pig. Results The histidine decarboxylase mRNA hybridization signal were detected in both of large and small cells.The TH immunoreactive substance distributed in cytoplasm steadly,but lacked in the nuclei,while the histamine immunoreactive substance distributed in cytoplasm nearby the plasmalemma.After chemical destroy of the guinea pig SCG′s neuron with 6-OHDA,the immunoreactive materials were hardly detected.Conclusion Because the histidine decarboxylase is the only enzyme which catalyzes histidine into histamine,histamine may be synthesized and coexisted with monoaminergic neurotransmitters in the superior cervical ganglia of guinea pig.