An improvement of blood sampling technique for Biomphalaria glabrata using anaesthesia and long-term relaxation and the role of this method in studies of the regulation of hemolymph glucose

Abstract 1. 1. A method is described which allows repeated collecting of hemolymph samples from Biomphalaria glabrata under nearly constant conditions with a minimum of manipulation. 2. 2. A modified Nembutal anaesthesia is followed by the fastening of the snail in a special apparatus in which it is rinsed with sterile tap water of constant temperature and kept muscle-relaxed by repeated injections of succinylcholine (SCh) at intervals of 3.5–5 hr. 3. 3. The results of hemolymph glucose determinations of 320 samples taken from 28 snails every 30 min over a period of 7 hr are presented in this paper. Thirteen well-relaxed snails had significantly lower glucose levels with significantly smaller variations (11.2 ∓ 4.30mg/100ml) than 15 poorly-relaxed snails (19.6 ∓ 9.48 mg/100 ml). 4. 4. Whereas the mean glucose level was kept constant in the well-relaxed snails over the period of investigation, glucose concentrations of the poorly-relaxed snails showed a significant rise. 5. 5. Both SCh and Nembutal have a negative chronotropic effect on the heart-beat of Biomphalaria glabrata which is tolerable in the present investigation. Neither of the two drugs has a significant effect on hemolymph glucose.