Abstract
Correlation studies were carried out between local anesthetic activity and systemic toxicity and between the former and irritancy. A very high correlation coefficient (r = 0.97) was found between the log of the Threshold Anesthetic Concentration5 (TAC5) of 25 compounds tested by intraspinal injection and the log of their LD50, determined by intravenous injection in mice.
A significant correlation (r = 0.74) was also found between the log of the TAC5 of 61 compounds tested by intradermal injection in guinea pigs and the log of the LD50 determrned by intravenous injection in mice.
A much lower correlation coefficient (r = 0.43) was obtained between the log of tile Threshold Irritant Concentration4 (TIC4) of 54 compounds deternlined by intradermal injection in rabbits (trypan blue method) and the log of the TAC5 determined by intradermal injection in guinea pigs.
These results suggest that a similar mechanism is responsible for the local anesthetic and the lethal effects of local anesthetics. A different mechanism appears to be responsible for local irritation, although in some cases, activity and irritancy may be modified in the same direction by certain structural changes in local anesthetic compounds.
Footnotes
- Received March 21, 1958.
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|
