A synthetic nanoreceptor, cucurbit[7]uril (CB[7]), fully encapsulated pentylenetetrazol (PTZ), a seizure-inducing model drug. As a consequence of the encapsulation, the development of PTZ induced convulsion behaviors in both larval zebrafish and mouse models were dramatically alleviated, suggesting that CB[7] holds great neuroprotection potential against neurotoxic drugs for clinical applications.