{'fraction_non_alphanumeric': 0.03171247357293869, 'fraction_numerical': 0.021141649048625793, 'mean_word_length': 5.230263157894737, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Protein kinase C‐independent sensitization of contractile proteins to Ca2+ in α‐toxin‐permeabilized smooth muscle cells from the guinea‐pig stomach

Involvement of protein kinase C in receptor‐operated Ca2+ sensitization of cell shortening was investigated by use of α‐toxin‐permeabilized smooth muscle cells from the fundus of the guinea‐pig. Most of the isolated cells responded to 0.6 μm Ca2+ with a maximal shortening to approximately 65% of the resting cell length. Addition of acetylcholine (ACh) at a maximal concentration (10 μm) resulted in a marked decrease in the concentration of Ca2+ required to trigger a threshold response from 0.6 μm to 0.2 μm. The augmentation of Ca2+ sensitivity by ACh was not inhibited by specific protein kinase C inhibitors, calphostin C and K‐252b at a concentration of 1 μm. These findings suggest that protein kinase C is not involved in the muscarinic receptor‐operated augmentation of Ca2+ sensitivity.