A phase 2 liver trial where the add-on drug didn't help — and the base drug quietly did
Read the Sunday Brief →

Study wrapper · #672

The Effect of Peptide Semax, an ACTH(4-10) Analogue, on Intracellular Calcium Dynamics in Rat Brain Neurons.

Kolbaev SN, Sharonova IN, Skrebitsky VG Bulletin of experimental biology and medicine. 2025.
Weak / noneIn vitroMentions: Semax

Editor's note

Using rat brain slices, researchers reported that 1 microM Semax increased the frequency of spontaneous calcium fluctuations in hippocampal CA1 pyramidal neurons but did not significantly change proton-induced calcium rises in cerebellar granule cells. The authors interpret this as evidence that Semax's neuroprotective action is not primarily mediated by blocking calcium entry through acid-sensing ion channels. This is a mechanistic ex-vivo electrophysiology study, useful for localizing where and how the peptide acts on neuronal networks, but far removed from clinical endpoints. It refines mechanism rather than demonstrating benefit. These are preclinical findings; human data are needed before clinical conclusions can be drawn.

Plain-language abstract

Semax is a peptide studied for protecting brain cells, but exactly how it works is not fully understood. Calcium movement inside neurons is central to how they signal and, when it goes wrong, how they get injured. Using thin slices of rat brain kept alive in the lab, researchers watched calcium activity inside neurons while applying Semax. In memory-related hippocampal cells, Semax increased the frequency of natural calcium 'blips.' In cerebellar cells exposed to acidic conditions (which mimic injury), Semax did not significantly change the calcium rise. The researchers concluded that Semax's protective effect probably does not come from blocking a particular acid-sensing calcium channel, and instead involves other targets in memory circuitry. This is early laboratory work aimed at understanding mechanism, not a test of benefit in animals or people.