it goes arnd n arnd thw whole song.. wiht sum kinda wah pedal or smthin..
and it follows tru the bass line...
its A Dm Fm and A...
[ Tab from: https://www.guitartabs.cc/tabs/t/tupac_shakur/hit_em_up_tab_ver_2.html ]
A Dm Fm
e-----5-----------5---------8-----------------------------------|
b-----5-----------6---------9-----------------------------------|
g-----6-----------7---------10----------------------------------|
d-----7-----------7---------10----------------------------------|
a-----7-----------5---------8-----------------------------------|
e-----5-----------x---------x-----------------------------------|