In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Injection of CYP ( n = 10 , 75 mg / kg , i . p . ) 2 hours prior to perfusion ( acute treatment ) of the animals increased Fos - immunoreactivity ( IR ) in neurons in the dorsal commissure , dorsal horn , and autonomic regions of spinal segments ( L1 - L2 and L6 - S1 ) which receive afferent inputs from the bladder , urethra , and ureter .
### Output Text:
Injection of <span class="chemical">CYP</span> ( n = 10 , 75 mg / kg , i . p . ) 2 hours prior to perfusion ( acute treatment ) of the animals increased Fos - immunoreactivity ( IR ) in neurons in the dorsal commissure , dorsal horn , and autonomic regions of spinal segments ( L1 - L2 and L6 - S1 ) which receive afferent inputs from the bladder , urethra , and ureter . 