{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,11]],"date-time":"2026-04-11T02:36:00Z","timestamp":1775874960369,"version":"3.50.1"},"reference-count":32,"publisher":"Wiley","issue":"7-8","license":[{"start":{"date-parts":[[2022,5,1]],"date-time":"2022-05-01T00:00:00Z","timestamp":1651363200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Synapse"],"published-print":{"date-parts":[[2022,6]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>4\u2010aminopyridine (4\u2010AP) is a potassium channel blocker that has been used to treat patients with multiple sclerosis and Lambert\u2013Eaton disease. The concentration of this drug in the blood of patients was estimated to be in low or submicromolar range. Animal studies have shown that 4\u2010AP at such low concentration selectively blocks a subset of channels in Kv1 or Kv3 families. The crayfish opener neuromuscular junction and ventral superficial flexor (VSF) preparations were used to examine functions of K<jats:sup>+<\/jats:sup> channels blocked by low concentrations of 4\u2010AP. At opener motor axons, intracellular recordings show that 4\u2010AP could increase action potential (AP) amplitude, duration, and after\u2010depolarization (ADP) at 10 \u03bcM. As 4\u2010AP concentration was increased, in twofold steps, AP amplitude did not increase further up to 5\u00a0mM. AP duration and ADP increased significantly mainly in two concentration ranges, 10\u201350 \u03bcM and 1\u20135\u00a0mM. The effects of 50 \u03bcM 4\u2010AP on the VSF were less consistent than that observed at the opener motor axons. 4\u2010AP did not change AP amplitude of motor axons recorded with an extracellular electrode and change in AP repolarizing potential was observed in \u223c25% of the axons. EPSP recorded simultaneously with AP showed an increase in amplitude with 4\u2010AP treatment only in 30% of the axon\u2010EPSP pairs. 4\u2010AP also increased firing frequencies of \u223c50% of axons. In four animals, 4\u2010AP \u201cawakened\u201d the firing of APs from an axon that was silent before the drug. The mixture of positive and negative 4\u2010AP effects summarized above was observed in the same VSF preparations in all cases (<jats:italic>n<\/jats:italic>\u00a0=\u00a08). We propose that there is a significant diversity in the density 4\u2010AP\u2010sensitive potassium channels among motor axons of the VSF. Functional significance in the differences of 4\u2010AP sensitivity of the two motor systems is discussed.<\/jats:p>","DOI":"10.1002\/syn.22234","type":"journal-article","created":{"date-parts":[[2022,4,23]],"date-time":"2022-04-23T19:48:15Z","timestamp":1650743295000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Functions of potassium channels blocked by low micromolar 4\u2010aminopyridine in the crayfish nervous system"],"prefix":"10.1002","volume":"76","author":[{"given":"Nicole","family":"Goldfeder","sequence":"first","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Riley","family":"McDonald","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah","family":"Gaston","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Amarri","family":"Harrison","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dong\u2010Ho","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Clara","family":"MacIntosh","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mauricio Moel","family":"Miranda","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emma","family":"Odom","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simmi","family":"Nishad","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"William","family":"Siwik","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Liangzhu","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6529-0622","authenticated-orcid":false,"given":"Jen\u2010Wei","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Biology Boston University  Boston Massachusetts"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2022,5]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.bpj.2021.01.013"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.010868"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.4206\u201013.2014"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1460\u20109568.2004.03730.x"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1152\/jn.00092.2005"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/s0361\u20109230(00)00335\u2010x"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1038\/43119"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.3892\/ol.2016.4123"},{"issue":"2","key":"e_1_2_8_10_1","first-page":"A140","article-title":"Application of a spike sorting procedure to analyze recordings in the crayfish ventral superficial flexor preparation: A high resolution approach to the study of neuromodulators on axons and synapses","volume":"12","author":"Inam Z. S.","year":"2014","journal-title":"Journal of Undergraduate Neuroscience Education"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2010.191973"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2008.153734"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.43.2.211"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.43.2.229"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.5291\u201014.2015"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuron.2011.06.024"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1152\/jn.00857.2011"},{"key":"e_1_2_8_18_1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.1703\u201017.2017"},{"key":"e_1_2_8_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0006\u20103495(90)82484\u2010X"},{"key":"e_1_2_8_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neulet.2016.01.061"},{"key":"e_1_2_8_21_1","doi-asserted-by":"publisher","DOI":"10.1007\/bf00612428"},{"key":"e_1_2_8_22_1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.3212\u201017.2018"},{"key":"e_1_2_8_23_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbc.2021.100302"},{"key":"e_1_2_8_24_1","doi-asserted-by":"publisher","DOI":"10.1016\/s0166\u20102236(00)01892\u20100"},{"key":"e_1_2_8_25_1","doi-asserted-by":"publisher","DOI":"10.1152\/jn.00176.2006"},{"key":"e_1_2_8_26_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0702041104"},{"key":"e_1_2_8_27_1","doi-asserted-by":"publisher","DOI":"10.1085\/jgp.98.6.1161"},{"key":"e_1_2_8_28_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1983.sp014942"},{"key":"e_1_2_8_29_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2014.276493"},{"key":"e_1_2_8_30_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.msard.2013.05.003"},{"issue":"1","key":"e_1_2_8_31_1","first-page":"260","article-title":"Effects of 4\u2010aminopyridine and 3,4\u2010diaminopyridine on transmitter release at the neuromuscular junction","volume":"227","author":"Thomsen R. H.","year":"1983","journal-title":"Journal of Pharmacology and Experimental Therapeutics"},{"key":"e_1_2_8_32_1","doi-asserted-by":"publisher","DOI":"10.1152\/jn.1978.41.1.85"},{"key":"e_1_2_8_33_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469\u20107793.1998.183bo.x"}],"container-title":["Synapse"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/syn.22234","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/syn.22234","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/syn.22234","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,8,23]],"date-time":"2023-08-23T22:57:20Z","timestamp":1692831440000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/syn.22234"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5]]},"references-count":32,"journal-issue":{"issue":"7-8","published-print":{"date-parts":[[2022,6]]}},"alternative-id":["10.1002\/syn.22234"],"URL":"https:\/\/doi.org\/10.1002\/syn.22234","archive":["Portico"],"relation":{},"ISSN":["0887-4476","1098-2396"],"issn-type":[{"value":"0887-4476","type":"print"},{"value":"1098-2396","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,5]]},"assertion":[{"value":"2021-09-27","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-04-15","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2022-05-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e22234"}}