CaMKIIa-hM3Dq-mCherry AAV (Serotype 9)

Recombinant adeno-associated viruses (AAV) are among the most widely used viral vectors in basic research due to their long-term efficacy and lack of pathogenicity. For nearly two decades, AAV vectors have been used to deliver transgenes to different components of the pain sensory system in rodents. Primary afferent neurons have been shown to be transduced via intrathecal, intraganglionic, intraneural, or peripheral injections. For example, intraspinal AAV vector delivery has greatly aided neuroanatomical and functional studies of dorsal horn circuits. In addition, intraparenchymal AAV injections within various brain nuclei have been used to map supraspinal circuits involved in pain processing.

AAV serotypes vary in their transduction efficiency via different routes of administration. Many serotypes have been identified for intraganglionic, intraspinal, intrathecal, and to a lesser extent peripheral delivery. AAV9 has been widely used to transduce cells of the sensory nervous system and has been shown to be more effective than other AAV serotypes when administered systemically in mice. AAV9 also effectively transduces motor, autonomic, and enteric neurons in mice. AAV9 is characterized by its ability to effectively transduce DRG neurons after intrathecal administration, as well as its ability to transduce neurons after local peripheral administration. AAV serotypes also differ in their ability to enter neurons through axon terminals and transport retrogradely to the cell body, a property that is particularly useful for targeting projection neurons of the central nervous system.