Changes in muscarinic acetylcholine receptors in the isolated duodenum from repeatedly cold-stressed rats and the effect of neurotropin.
In rats repeatedly cold-stressed by specific alternation of rhythm in environmental temperature (SART-stressed rats), the contractile response to acetylcholine (ACh) of the isolated duodenum was remarkably decreased, whereas the contractile responses to K+, Ba2+ and Ca2+ were comparable to those in non-stressed rats. The amount of [3H]quinuclidinyl benzilate in the duodenum of SART-stressed rats was about 50% of that in non-stressed rats, but the KD value remained unchanged. Long-term administration of hexamethonium prevented the changes in SART-stressed rats. The daily treatment with Neurotropin, an extract isolated from inflamed rabbit dermis inoculated with vaccinia virus, dose-dependently prevented the changes in SART-stressed rats. However, Neurotropin had no effect on the ACh-induced decrease in muscarinic ACh receptor (m-ACh.R) in cultured vas deferens of guinea pig. These results suggest that down-regulation of m-ACh.R in duodenum by SART stress may be associated with enhanced activity in the parasympathetic center. Moreover, Neurotropin is thought to prevent the down-regulation of m-ACh.R throughout the central nervous system.
Namimatsu
A
A
Institute of Bio-active Science, Nippon Zoki Pharmaceutical Co., Ltd., Hyogo, Japan.
Go
K
K
Ohara
H
H
Yoneda
R
R
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D003080:Cold Temperature / Q000009:adverse effects; D015536:Down-Regulation / Q000187:drug effects; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D006168:Guinea Pigs; D007551:Isotonic Contraction / Q000187:drug effects; D008297:Male; D009924:Organ Culture Techniques; D011134:Polysaccharides / Q000494:pharmacology*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism*; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism
D011134:Polysaccharides; D011976:Receptors, Muscarinic; C010491:neurotropin; D011813:Quinuclidinyl Benzilate; D000109:Acetylcholine