Antinociception plasticity

All five muscarinic receptor subtypes have been detected in the central nervous system. The roles of Mx through M3 have been analyzed by means of experiments in knockout mice. The Mx subtype is richly expressed in brain areas involved in cognition. Knockout of Mx receptors was associated with impaired neuronal plasticity in the forebrain, and pilocarpine did not induce seizures in Mx mutant mice. The central nervous system effects of the synthetic muscarinic agonist oxotremorine (tremor, hypothermia, and antinociception) were lacking in mice with homozygously mutated M2 receptors. Animals lacking M3 receptors, especially those in the hypothalamus, had reduced appetite and diminished body fat mass. 

Malmberg-Aiello P, Lamberti C, Ghelardini C, Giotti A, Bartolini A (1994) Role of histamine in rodent antinociception. Br J Phtirmacol 111 1269-1279 MameU M, Carta M, Partridge LD, Valenzuela CF (2005) Neurosteroid-induced plasticity of immature synapses via retrograde modulation of presynaptic NMDA receptors. J Neurosci... 

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