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Effects of lectins on quantal release at the frog neuromuscular junction
| Content Provider | Semantic Scholar |
|---|---|
| Author | Gu, Xiaoping Kloot, William Van Der |
| Copyright Year | 1992 |
| Abstract | This work was initiated because pretreatment with concanavalin A was reported to abolish the increase in spontaneous quantal release produced by hypertonic solutions [Gorio A. and Mauro A. (1979) J. gen. Physiol. 73, 245-263]. This suggested that lectins might be valuable tools for investigating the role of glycoproteins in the response to tonicity. We compared muscles soaked for 2 h in hypertonic solution containing concanavalin A with paired muscles soaked in hypertonic solution without lectin. The lectin treatment decreased miniature end-plate potential frequencies in Ringer and in hypertonic solutions compared with the controls. Even after lectin treatment hypertonic solutions and elevated K+ solutions increased miniature end-plate potential frequencies, and the proportional increases were the same as in controls. The lectin treatment lowered baseline frequency, but the preparation still responded to hypertonic solutions. Concanavalin A effects appeared after treatment for more than 1 h and required concentrations of 10 micrograms/ml or higher. Higher concentrations did not produce more effect. Similar results were obtained with four other lectins with different sugar specificities. Treatment in hypertonic solution without lectin produces a similar, but smaller, decrease in baseline frequency. Concanavalin A pretreatment had no detectable effects on evoked release or facilitation. We conclude that the effects of lectins on quantal release are not mediated by binding to a single sugar group. The lectins do not produce a unique effect; they exaggerate the changes produced by hypertonic pretreatment. All of the effects could be accounted for by a reduction in baseline [Ca2+] in the nerve terminal. Such reductions are produced by lectins in many cell types. |
| Starting Page | 649 |
| Ending Page | 656 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0306-4522(92)90173-Y |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/030645229290173Y |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/030645229290173Y?dgcid=api_sd_search-api-endpoint |
| PubMed reference number | 1584412 |
| Alternate Webpage(s) | https://doi.org/10.1016/0306-4522%2892%2990173-Y |
| Journal | Medline |
| Volume Number | 47 |
| Journal | Neuroscience |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
