Studies have shown that inhibition of cholinergic neurotransmission decreased the release of acetylcholine.[87] Degenerative changes in autonomic nerves were associated with the development of osteoporosis.[88] Muscarinic and nicotinic acetylcholine receptors (mAChR and nAChR) were expressed in osteoblasts.[89] mAChR M3R stimulated cancellous bone microarchitecture, bending stiffness, and bone matrix synthesis, and was a positive regulator of increased bone mass.[90, 91] Flexural stiffness and maximum breaking force were significantly reduced in nAChR subunit α9 KO mice. The gene discussed is CHRNA4; the disease is osteoporosis.