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THE RELEASE OF ACETYLCHOLINE FROM MAMMALIAN MOTOR NERVE ENDINGS
Author(s) -
STRAUGHAN D. W.
Publication year - 1960
Publication title -
british journal of pharmacology and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0366-0826
DOI - 10.1111/j.1476-5381.1960.tb01266.x
Subject(s) - acetylcholine , free nerve ending , motor nerve , neuroscience , neuromuscular junction , chemistry , medicine , anatomy , biology , pharmacology
The release of acetylcholine from rat and guinea‐pig isolated diaphragm preparations stimulated through the phrenic nerve was optimal at 37° in Krebs solution with 5 × 10 −6 neostigmine methylsulphate. The amount of acetylcholine released by a 20 min. tetanus was reduced by cooling. At frequencies of stimulation above 6/sec. the release was less than that predicted. This “failure” was unaffected by the addition of 1 × 10 −6 choline. The acetylcholine release declined with continued stimulation at 25/sec. In the absence of nerve stimulation, there was a small continuous resting release of acetylcholine which seemed to originate in the muscle fibres. These results are discussed in the light of current electrophysiological knowledge of the quantal release of acetylcholine.