Combined administration of anisodamine and neostigmine produces anti-shock effects: involvement of α7 nicotinic acetylcholine receptors

Aim:

To evaluate the anti-effects of anisodamine and neostigmine in animal models of endotoxic and hemorrhagic shock.

Methods:

Kunming mice were injected with lipopolysaccharide (LPS 30 mg/kg, ip) to induce endotoxic shock. Anisodamine (12.5, 25, and 50 mg/kg, ip) and neostigmine (12.5, 25, and 50 μg/kg, ip) were administered immediately after LPS injection. Survival rate was monitored, and the serum levels of TNF-α and IL-1β were analyzed using ELISA assays. The effects of anisodamine and neostigmine were also examined in α7 nicotinic acetylcholine receptor (α7 nAChR) knockout mice with endotoxic shock and in Beagle dogs with hemorrhagic shock.

Results:

In mice with experimental endotoxemia, combined administration of anisodamine and neostigmine significantly increased the survival rate and decreased the serum levels of inflammatory cytokines, as compared to those produced by either drug alone. The anti-shock effect of combined anisodamine and neostigmine was abolished in α7 nAChR knockout mice. On the other hand, intravenous injection of the combined anisodamine and neostigmine, or the selective α7 nAChR agonist PNU282987 exerted similar anti-shock effects in dogs with hemorrhagic shock.

Conclusion:

The results demonstrate that combined administration of anisodamine and neostigmine produces significant anti-shock effects, which involves activation of α7 nAChRs.     

Rat neuronal nicotinic acetylcholine receptors containing α7 subunit： pharmacological properties of ligand binding and function

Aim： To compare pharmacological properties of heterologously expressed homomeric α7 nicotinic acetylcholine receptors （α7 nAChRs） with those of native nAChRs containing α7 subunit （α7＊ nAChRs） in rat hippocampus and cerebral cortex. Methods： We established a stably transfected HEK-293 cell line that expresses homomeric rat α7 nAChRs. We studies ligand binding profiles and functional properties of nAChRs expressed in this cell line and native rat α7＊ nAChRs in rat hippocampus and cerebral cortex. We used [125Ⅰ]-α-bungarotoxin to compare ligand binding profiles in these cells with those in rat hippocampus and cerebral cortex. The functional properties of the α7 nAChRs expressed in this cell line were studied using whole-cell current recording. Results： The newly established cell line, KXα7R1, expresses homomeric α7 nAChRs that bind [125Ⅰ]-α-bungarotoxin with a Kd value of 0.38±0.06 nmol/L, similar to Kd values of native rat α7＊nAChRs from hippocampus （Kd=0.28±0.03 nmol/L） and cerebral cortex （Kd=0.33±0.05 nmol/L）. Using whole-cell current recording, the homomeric α7 nAChRs expressed in the cells were activated by acetylcholine and （-）-nicotine with EC50 values of 280±19μmol/L and 180±40μmol/L, respectively. The acetylcholine activated currents were potently blocked by two selective antagonists of α7 nAChRs, a-bungarotoxin （IC50=19±2 nmol/L） and methyllycaconitine （IC50=100±10 pmol/L）. A comparative study of ligand binding profiles, using 13 nicotinic ligands, showed many similarities between the homomeric α7 nAChRs and native α7＊receptors in rat brain, but it also revealed several notable differences. Conclusion： This newly established stable cell line should be very useful for studying the properties of homomeric α7 nAChRs and comparing these properties to native α7＊ nAChRs.