Author/Editor     Bergant, Aleksandra; Suhadolčan, Lovro
Title     Množina in vezava acetilholinesteraze v motoričnih ploščicah podganjih mišic
Type     monografija
Place     Ljubljana
Publisher     Medicinska fakulteta
Publication year     2005
Volume     str. 44
Language     slo
Abstract     Background. Acetylcholinesterase (AChE) in the neuromuscular junction (NMJ) terminates the impulse transmission by rapid hydrolysis of neurotransmitter acetylcholine. The activity of AChE is considerably higher in the fast muscle than in the slow muscle, but the quantity of AChE in NMJ in fast and slow muscles has never been directly measured. Two types of binding of the asymmetric molecular forms of AChE in the NMJ basal lamina have been demonstrated, but the opinions regarding the ratio between electrostatically and covalently bound AChE are contradictory. Aim. We intended to modify a histological method for visualising AChE with fluorescently-conjugated fasciculin-2 (FAS-2) to a method for direct determination of the quantity of AChE in the NMJ. Using that, we could quantitatively estimate the amount of AChE in the synaptic cleft in fast and slow muscles and the share of the asymmetric forms of AChE, that are bound electrostatically. Hypothesis. We tested the following two hypotheses: a) quantity of AChE, bound in NMJ basal lamina, is lower in slow muscles than in fast muscles of the rat, and b) asymmetric forms of AChE in the rat fast muscle NMJ are mainly electrostatically bound, only a minor share is bound covalently. Methods. The experiments were performed on five male Wistar rats. Ten soleus (SOL) muscles and ten sternomastoid (STM) muscles were used. We introduced a method for visualising AChE in the NMJ with FAS-2, conjugated with Oregon-Green fluorophore, and tested its adequacy by comparing it to a standard histochemical method for visualising AChE in tissue. The electrostatically bound AChE was solubilised by incubation in a high ionic strenght medium with calcium chelating agent. (Abstract truncated at 2000 characters).
Descriptors     ACETYLCHOLINESTERASE
MOTOR ENDPLATE
MUSCLE, SKELETAL
HISTOCYTOCHEMISTRY
FLUORESCENT DYES
RATS, WISTAR