Receptors thermally responsive

Further experimental evidence for the involvement of SP in pain perception came from knock-out animals. Mice, in which the preprotachykinin A gene was disrupted, showed significantly reduced responses in tests that involved more intense noxious stimuli (Cao et al., 1998). De Felipe et al. (1998) disrupted the N receptor, and found the characteristic amplification ( wind up ) and intensity coding of nociceptive reflexes to be absent. NK receptor knockout mice show no changes in acute nociception tests. In contrast, SP and NKi receptor knock-out mice show reduction in responses to inflammatory stimuli. Nerve injury-induced mechanical but not thermal hyperalgesia is attenuated in NKi receptor knock-out mice, when inducing chronic neuropathic pain by unilateral ligation of the L5 spinal nerve (Mansikka et al., 2000). 

In spite of all their advantages, sensitivity and selectivity, bio-sensors, however, do possess disadvantages connected with thermal and timely instability, high cost of bio-receptors and the need to add substrates in the solution under analysis as signal-generating substances. Some attempts to synthesize and use as receptors chemical organic catalytic systems, which will ensure the required selectivity and response rate, have become the basis for developing enzyme-free sensors [11], or biomimetic sensors. 

Cannabinoids produce antinociception through multiple mechanisms at peripheral, spinal and supraspinal levels through CBi and CB2 cannabinoid receptors in several animal species, including mice, rats, rabbits, cats, dogs, monkeys and humans (Pertwee 2001). These responses were revealed in multiple acute nociceptive models using thermal (Buxbaum 1972 Hutcheson et al. 1998 Martin and Lichtman 1998), mechanical (Smith et al. 1998), chemical (Bicher and Mechoulam 1968 Welch et al. 1995) and electrical stimuli (Bicher and Mechoulam 1968 Weissman et al. 1982). Cannabinoid agonists also induce antinociception in inflammatory... 

The action of lobeline (237) as a nicotinic receptor agonist has continued to generate considerable interest. (-)-Lobeline demonstrated a potent hyperalgesic effect, similar to that of nicotine, when tested in the low intensity thermally evoked tail avoidance response assay [514]. It improved cognition and retention in rats comparably to nicotine [515]. Both 237 and nicotine exhibited anxiolytic effects in mice [516] and partially inhibited iV-methyl-D-aspartate-induced responses in rat cortical neurons in vitro [517]. It was a potent inhibitor of nicotine-induced prostration in rats (ED50 = 10 nM) and antagonized additional actions of nicotine including systolic blood pressure increases, seizure, and death [518]. 

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