Antisense inhibition of neuronal nicotinic receptors in the tobacco-feeding insect, Manduca sexta.

Acetylcholine is the predominant excitatory transmitter in the insect central nervous system with many of its effects mediated by nicotinic acetylcholine receptors. These receptors are present at very high density and are structurally heterogeneous, although little is known about functional distinctions between them. An interesting system for examining these receptors is the larval stage of Manduca sexta, a nicotine-resistant tobacco-feeding insect. The nicotinic responses of cultured neurons were found to be blocked by mecamylamine and curare but highly resistant to alpha-bungarotoxin. The responses were also unaffected by the reducing agent dithiothreitol and the alkylating agent bromoacetylcholine suggesting that the alpha-subunit dicysteine agonist binding site is protected. To begin determining the functional roles of different subunits in these receptors, cultured neurons were treated with oligonucleotides based on the gene sequence of the alpha subunit, MARA1. Antisense DNA caused a significant downward shift in the amplitude distribution of nicotinic responses compared to sense or reverse antisense treatments. These treatments did not affect currents mediated by the application of GABA. The reduction in the nicotinic depolarization and inward currents did not affect the rate of current onset or recovery, suggesting that antisense MARA1 causes a partial block of all nicotinic responses in these neurons. These results demonstrate that receptor gene expression in insect neurons can be manipulated in a sequence-specific manner by antisense treatment and they provide evidence that MARA1 is important for normal nicotinic responses in Manduca.

Fickbohm D ，Trimmer BA 《ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY》

Expression and function of two nicotinic subunits in insect neurons.

Vermehren A ，Trimmer BA 《journal of neurobiology》

Alpha 6 and gamma 2 subunit antisense oligodeoxynucleotides alter gamma-aminobutyric acid receptor pharmacology in cerebellar granule neurons.

Zhu WJ ，Wang JF ，Vicini S ，Grayson DR ... -  《MOLECULAR PHARMACOLOGY》

Diversity of nicotinic acetylcholine receptors in rat hippocampal neurons. I. Pharmacological and functional evidence for distinct structural subtypes.

Alkondon M ，Albuquerque EX 《JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS》

Pharmacological properties of nicotinic acetylcholine receptors expressed by guinea pig small intestinal myenteric neurons.

Zhou X ，Ren J ，Brown E ，Schneider D ，Caraballo-Lopez Y ，Galligan JJ ... -  《JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS》