If a certain meditation releases a lot of dopamine/serotonin, etc; is there a probability that overdoing it could down-regulate receptors in my brain?

Serontinergic: Receptors do down regulate when a medication is used, they up regulate when there is no seratonin. Down regulation of Dopamine receptors does occur in cases of abuse with cocaine, high dose amphetamine , etc, not with common medications for mood. Also people may have different levels of receptors without meds, thrill seekers needing more Dopamine release to feel a charge, .