Details

Autor(en) / Beteiligte

• Yamada, Takehiro
• Murayama, Toshihiko
• Nomura, Yasuyuki

Titel

Muscarinic Acetylcholine Receptors on Rat Thymocytes: Their Possible Involvement in DNA Fragmentation

Ist Teil von

• The Japanese Journal of Pharmacology, 1997, Vol.73(4), pp.311-316

Ort / Verlag

The Japanese Pharmacological Society

Erscheinungsjahr

1997

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• Several studies have shown that the nervous (and hormonal)system controls immune functions. In the present study, we examined the presence of muscarinic acetylcholine receptors and the effect of carbachol on DNA fragmentation in adult rat thymocytes. Rat thymocytes possessed high affinity binding sites for the muscarinic antagonist [3H]3-quinuclidinyl benzilate (QNB). The average number of binding sites per cells was 3000, and the equilibrium dissociation constant of [3H]QNB on intact cell was approximately 80 nM. The binding was inhibited by an Ml and M3-selective antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodine (4-DAMP). Hydrocortisone (100 mg/kg, s.c.)treatment of rats for 2 days prior to sacrifice increased the average number of [3H]QNB binding sites on thymocytes by 82±33%. The gel electrophoresis of DNA extracted from carbachol-treated thymocytes revealed a ladder pattern typical of intranucleosomal fragmentation. The addition of oxotremorine-M also induced DNA fragmentation and the effects of muscarinic agonists were inhibited by the addition of atropine or 4-DAMP. The results suggest the existence of muscarinic receptors and the possible involvement in apoptosis in thymocytes.