Car7, also known as carbonic anhydrase VII, is an enzyme that belongs to the alpha-carbonic anhydrase family. It plays a role in the regulation of neuronal pH, specifically enhancing bicarbonate-driven GABAergic excitation during intense GABAA-receptor activation [1,3]. In the mouse brain, it has a wide expression pattern, detected in the pia, choroid plexus, neurons of the cortical layer, thalamus, medial habenulae, pyramidal and granular cells of the hippocampus, and Purkinje cells in the cerebellum [1]. In the mouse digestive system, it has extremely low expression levels but is expressed in all tissues examined [4]. In stroke-prone spontaneously hypertensive rats, high salt intake leads to significant underexpression of Car7 in the kidneys [2].

Using a Car7 knockout (KO) mouse model, it was found that P13-14 CA VII KO mice show behavioural manifestations atypical of experimental febrile seizures (eFS) and a complete absence of electrographic seizures, indicating that Car7 is a key molecule in age-dependent neuronal pH regulation with consequent effects on generation of FS [3].

In conclusion, Car7 is crucial for neuronal pH regulation, especially in relation to febrile seizures as demonstrated by KO mouse models. Its abnormal expression in the kidneys under high-salt conditions in rats also suggests a potential role in renal-related physiological processes. The study of Car7 using these genetic models helps in understanding its biological functions and its implications in specific disease-related conditions.