The activation of the efferent vestibular systemmodifies the basal discharge and the dynamic response of primary-afferent neurons to headmotion and gravitational stimuli. The efferent input to afferent neurons is mediated primarily by cholinergic synapses that activate both muscarinic and nicotinic receptors. Previously we had shown that themuscarinic-acetylcholine-receptor (mAChR) activationmo...

Repetitive visual training paired with electrical activation of cholinergic projections to the primary visual cortex (V1) induces long-term enhancement of cortical processing in response to the visual training stimulus. To better determine the receptor subtypes mediating this effect the selective pharmacological blockade of V1 nicotinic (nAChR), M1 and M2 muscarinic (mAChR) or GABAergic A (GABA...

The interaction between a novel G protein-coupled receptor modulator, N-(2,3-diphenyl-1,2,4-thiadiazole-5-(2H)-ylidene) methanamine hydrobromide (SCH-202676), and the M(1) muscarinic acetylcholine receptor (mAChR) was investigated. In contrast to the prototypical mAChR allosteric modulator, heptane 1,7-bis-(dimethyl-3'-phthalimidopropyl)-ammonium bromide (C(7)/3-phth), SCH-202676 had no effect ...

BACKGROUND, AIM, AND SCOPE Hexanitrohexaazaisowurtzitane (CL-20) is a relatively new energetic compound sharing some degree of structural similarity with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a known neurotoxic compound. Previously, we demonstrated using a noninvasive electrophysiological technique that CL-20 was a more potent neurotoxicant than RDX to the earthworm Eisenia fetida. In ...

Previous studies suggest that selective antagonists of specific subtypes of muscarinic acetylcholine receptors (mAChRs) may provide a novel approach for the treatment of certain central nervous system (CNS) disorders, including epileptic disorders, Parkinson's disease, and dystonia. Unfortunately, previously reported antagonists are not highly selective for specific mAChR subtypes, making it di...

Modulatory mechanisms of object-recognition memory in the perirhinal cortex Nicole Gervais, Ph.D. Concordia University, 2014 The present thesis examined whether acetylcholine (ACh) and 17-β estradiol (E2) modulate object-recognition memory (ORM) and perirhinal cortex (PRh) function. ORM was assessed using the Novel-Object Preference (NOP) test or the delayed non-match-to-sample (DNMS) task. The...

Chlorpyrifos (CPS) is a widely used diethyl organophosphorus insecticide in agricultural settings. Household and urinary residue analysis has suggested that children in agricultural communities are at risk of exposure to diethyl organophosphorus insecticides. The effects of repeated postnatal exposure to CPS and its metabolite chlorpyrifos-oxon (CPO) on total muscarinic acetylcholine receptor (...

The pathogenesis of chagasic cardiomyopathy is not completely understood, but it has been correlated with parasympathetic denervation (neurogenic theory) and inflammatory activity (immunogenic theory) that could affect heart muscarinic acetylcholine receptor (mAChR) expression. In order to further understand whether neurogenic and/or immunogenic alterations are related to changes in mAChR expre...

31 Acetylcholine (ACh), acting at muscarinic ACh receptors (mAChRs), modulates the 32 excitability and synaptic connectivity of hippocampal pyramidal neurons. CA1 pyramidal 33 neurons respond to transient (" phasic ") mAChR activation with biphasic responses in 34 which inhibition is followed by excitation, whereas prolonged (" tonic ") mAChR activation 35 increases CA1 neuron excitability. Bot...

Gq-coupled, M1 muscarinic acetylcholine receptors (mAChRs) facilitate hippocampal learning, memory, and synaptic plasticity. M1 mAChRs induce long-term synaptic depression (LTD), but little is known about the underlying mechanisms of mAChR-dependent LTD and its link to cognitive function. Here, we demonstrate that chemical activation of M1 mAChRs induces LTD in hippocampal area CA1, which relie...