Tail flick test

Similar to tobacco, lobelia may also have analgesic effects. However, it depends on the mode of administration (Damaj et al. 1997). Intrathecal lobeline produces analgesia on the tail-flick test, but subcutaneous administration is ineffective. On the other hand, subcutaneous lobeline dose-dependently enhances nicotine analgesia. Tolerance develops to this effect of lobeline after 10 days. Lobeline can also produce hyperalgesic effects when administered into the dorsal posterior mesencephalic tegmentum (Hamann and Martin 1994). However, the relevance of this to peripheral administration of lobelia is questionable because chronic injections (IP) of lobeline in rats induced no changes in tail-flick latencies (Sopranzi et al. 1991). 

Interactions are seen between cocaine and the opioid system in analgesia. A synergistic effect occurs when cocaine is combined with a ju agonist (morphine) in the hot-plate test and a k agonist (U69,593) in the hot-plate test (Waddell and Holtzman 1999). Cocaine enhances morphine analgesia in several analgesic paradigms (e.g., formalin test, hot-plate test, and thermal tail-flick test)... 

Interestingly, one study has shown that cocaine may be a direct antagonist at nicotinic receptors (Damaj et al. 1999). Cocaine blocks several of nicotine s effects, including analgesia on the tail-flick test, independent of its monoamine activity or local anesthetic effects. 

In the above discussion on the mu/kappa receptor selectivity of the U-50488 (5) series, the steric properties of the tertiary amine and the distance between the amide and the aromatic ring were cited as important factors. This has been exploited by the Upjohn company to give the arylformamide-dimethyl-amine derivative (52) which is an analgesic in the mouse tail flick test (ED50 = 0.2 mg/kg s.c.) and causes mu-opioid like side-effects such as Straub tail, arched back and increased locomotor activity [81]. These behavioural effects and the association constant for the morphine receptor of compound... 

This derivative is one of the most potent morphine-antagonists yet examined (19 X nalorphine in rats [221]) and it gives no analgesic response in the mouse hot-plate and rat tail-flick tests [222]. It is inactive, furthermore, in the mouse... 

Some 1,4-benzodiazepine derivatives, loosely regarded as cyclic versions of basic anilide analgesics, antagonize pethidine in the rat tail-flick test [246]. Activity orders are about 200 times below that of nalorphine for some 4-allyl... 

Lutfy, K., Cai, S.X., Woodward, R.M., Weber, E. Antinociceptive effects on NMDA and non.NMDA receptor antagonists in the tail flick test in mice, Pain 1997, 76, 31-40. 

SNC80 dose dependently produces antinociception in the mouse warm water tail flick test (i.c.v., i t. and i.p.)... 

A model of thermal pain. Mice or rats are placed on a heated metal plate of variable temperature. Depending on the temperature (48-58 °C), a weak or strong pain stimulus is induced. Animals respond either by licking their paws or by jumping. Analgesics increase the latency for this pain reaction. The low temperature hot plate detects a broader spectrum of less efficacious analgesics in comparison to its high temperature modification or the tail flick test (Eddy and Leimbach J. Pharmacol. 1953, 107, 385). 

Gilron, I., Biederman, J., Jhamandas, K., and Hong, M. (2003). Gabapentin blocks and reverses antinociceptive morphine tolerance in the rat pawpressure and tail-flick tests. Anesthesiology 98,... 

Figure 1 Time course for effects of the mixed opioid agonist DPI-3290 on anti-nocieption and blood pC02 levels in alfentanil-infused rats. Alfentanil was intravenously infused at 6 pg/kg/min. At the time points outlined in the figure, radiant tail flick testing and arterial blood samples were collected and analyzed by standard methods. Antinociception was expressed as maximal percent effect (MPE).

Figure 5 Antinociceptive effects of biphalin (0.005 pg) and morphine (2.5 pg) administered intrathecally to rats measured by tail flick test. There is a significantly greater difference ( P <. 05 t-test) in the antinociceptive effect of morphine as compared to biphalin 120 min after injection.

Figure 3 Antinociceptive response observed after IV administration of RB 101 and antagonism by naloxone and naltrindole in the rat tail flick test. The results are expressed as percent analgesia SEM (n = 8) for each group. P <. 05 P <. 01 as compared to control P <. 05 as compared to the same dose without antagonist (Newman-Keuls test).

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