Acid-base status of a pulmonate land snail (Helix aspersa) and a prosobranch amphibious snail (Pomacea bridgesi) during dormancy
✍ Scribed by Scholnick, David A. ;Snyder, Gregory K. ;Spell, Angel R.
- Book ID
- 102893091
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 614 KB
- Volume
- 268
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Changes in metabolism and acid‐base status were compared during dormancy in the pulmonate land snail Helix aspersa and a prosobranch amphibious snail Pomacea bridgesi. The typical condition of higher blood PCO~2~ and bicarbonate levels for air‐breathing versus water‐breathing vertebrates was shown for the two snail species. When exposed to dry air for 24 hr, both species depressed oxygen uptake by about 65%. In Pomacea, hypercapnia (increase in hemolymph PCO~2~ from 5.5 to 18 torr) resulting from dormancy produced no significant change in pH due to large increases in bicarbonate (over 17 mmol/l). In Helix, on the other hand, hypercapnia (increase in hemolymph PCO~2~ from 13 to 18 torr) resulting from dormancy produced a significant decrease in pH and a less than 7 mmol/l increase in bicarbonate. Pre‐existing high levels of bicarbonate in Helix may prevent compensation of hypercapnia resulting from dormancy, similar to the case described for air‐breathing vertebrates. Complete compensation of respiratory acidosis during the first 24 hr of dormancy in Pomacea suggests that metabolic rate suppression is independent of pH. © 1994 Wiley‐Liss, Inc.