Table 2.

Cellular localization of adenosine A₁, A_2a, A_2b, and A₃ receptor immunoreactivities in human small and large intestine

Human intestinal region/cell type	A1	A2a	A2b	A3
Jejunum				+
Longitudinal muscle	±	±	-
Myenteric plexus neurons	+	+	+
Glia	-	-	+++
Circular muscle	+	-	-
Submucous plexus neurons	-	+++	+++
Nerve fibers/neurites	-	+	+	+
Epithelia	-	+	+	+
Colon				+
Longitudinal muscle	±	-	-
Myenteric plexus neurons	-	+	+
Glia	-	-	+
Circular muscle	+	+	+
Submucous plexus neurons	+++	+	+
Epithelia	+
T98G				+
U373				+
BON cells				+

- absent, + present (or present ≤ 2 neurons), ± marginally detectable, ++ 3-6 neurons, +++ > 6 neurons. (Modified from [19] by permission)