Figure 8.
Site of action of coffee on smooth muscle contractions in the ileum. Ileal muscle strips were isolated from naïve rats, and their longitudinal muscle contractile activities were recorded in a muscle bath. The contractile response to regular coffee (Coff) and decaffeinated coffee (Decaf) at 5 mg/mL each was recorded in the absence and presence of nicotinic receptor antagonist hexamethonium (Hex, 10−4 M) (A), muscarinic receptor antagonist atropine (Atr, 10−6 M) (B), and neurotoxin tetrodotoxin (TTX, 10−6 M) (C). Tracings are representative of 4~5 independent experiments. The response in the first 2 min after the addition of coff or decaf over baseline activity is summarized in the bar graphs. N = 4 or 5. * p < 0.05.