Intragastric DMXB-A, an alpha7 nicotinic agonist, improves deficient sensory inhibition in DBA/2 mice.
BACKGROUND
Abnormal sensory inhibition is observed in the majority of schizophrenic patients. DBA/2 mice spontaneously exhibit a similar deficit in sensory inhibition and thus provide a model for drug development targeted to this physiologic abnormality. The impaired sensory inhibition is characterized by diminished response of the hippocampal evoked potential to the second of closely paired auditory stimuli (500-m/sec interstimulus interval). Subnormal levels of hippocampal alpha7 nicotinic cholinergic receptors are associated with the deficient sensory inhibition in both DBA/2 mice and people with schizophrenia.


METHODS
Our study examined the inhibition of the P20-N40 auditory evoked potential in DBA/2 mice after intragastric administration of DMXB-A (3-2,4-dimethoxybenzylidine anabaseine), an alpha7 nicotinic receptor partial agonist. After presentation of auditory stimuli, electroencephalographic responses were recorded and measured to monitor the effects of the DMXB-A, alone and in combination with selective nicotinic antagonists.


RESULTS
Gastric administration of DMXB-A (10 mg/kg) improved sensory inhibition in DBA/2 mice. This improvement was blocked by alpha-bungarotoxin, but not mecamylamine, indicating that DMXB-A exerts its effects through the alpha7 nicotinic receptor.


CONCLUSIONS
Intragastrically administered DMXB-A improves deficient sensory inhibition in DBA/2 mice through stimulation of alpha7 nicotinic receptors. These studies agree with results from previous studies with subcutaneously administered DMXB-A.
Simosky
J K
JK
Department of Pharmacology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
Stevens
K E
KE
Kem
W R
WR
Freedman
R
R
D000161:Acoustic Stimulation; D000284:Administration, Oral; D000818:Animals; D001597:Benzylidene Compounds / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D001921:Brain / Q000378:metabolism; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology / Q000601:surgery; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D009433:Neural Inhibition / Q000187:drug effects* / Q000502:physiology; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D011725:Pyridines / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism
D001597:Benzylidene Compounds; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011725:Pyridines; D011978:Receptors, Nicotinic; C088936:3-(2,4-dimethoxybenzylidene)anabaseine