Table 1.

Distribution of PACAP in the GI tract of various mammals’ species.

Species	Localization	References
Oesophagus
Rat	nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and in the mucosa	[7]
Pig	nerve terminals in the striated muscle	[23]
Human	neurons in the myenteric ganglia intraganglionic nerve fibers in the myenteric ganglia nerve fibers in the circular and longitudinal muscle layers	[27] [27] [28]
Cat	nerve fibers in the myenteric ganglia and muscle layers	[19]
Sheep	nerve fibers in the myenteric ganglia and muscle layers	[19,33]
Ferret	nerve fibers in the myenteric ganglia and muscle layers	[19]
Stomach
Rat	nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and in the mucosa neurons in the myenteric ganglia the enterochromaffin-like (ECL) cells in the mucosa	[7,18] [7,18] [17]
Mouse	nerve fibers in the mucosa nerve fibers in the circular muscle layer in the antrum	[19] [20]
Pig	neurons in the myenteric and submucous plexuses in the corpus and prepyloric area	[11,24]
Human	nerve fibers in the mucosa and muscle layers cells in the gastric glands	[19] [28]
Cat	nerve fibers in the myenteric ganglia, muscle layers and mucosa cells in the gastric glands	[19,28]
Sheep	nerve fibers in the myenteric ganglia and muscle layers	[19,33]
Ferret	nerve fibers in the myenteric ganglia and muscle layers	[19]
small intestine
Rat	neurons in the myenteric and submucous plexuses nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and in the mucosa	[7,9,16]
Mouse	nerve fibers in the myenteric ganglia and smooth muscle	[19]
Guinea pig	nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and around blood vessels of the submucosa neurons in the myenteric ganglia	[21,22]
Pig	neurons in the myenteric plexus, outer submucous plexus, and inner submucous plexus nerve fibers in the mucosa and both muscular layers in the ileum	[10,11,12,25,26]
human	neurons in the myenteric and submucous ganglia nerve fibers in the circular and longitudinal muscle layers, in the mucosa and in the enteric ganglia	[19]
Cat	nerve fibers in the myenteric ganglia and muscle layers	[19]
Sheep	nerve fibers in the myenteric ganglia and muscle layers and arterial walls	[19,33]
Ferret	nerve fibers in the myenteric ganglia and muscle layers	[19]
large intestine
Rat	neurons in the myenteric and submucous plexuses nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and in the mucosa	[7,9,16]
Guinea pig	nerve fibers in the circular and longitudinal muscle layers, myenteric and submucous plexuses and around blood vessels of the submucosa neurons in the myenteric ganglia	[21,22]
Pig	neurons in the myenteric plexus, outer submucous plexus, and inner submucous plexus in the descending colon nerve fibers in the circular and longitudinal muscle layers, in the mucosa and in the enteric plexuses	[10,11]
Human	neurons in the myenteric plexus and submucous plexus nerve fibers in both enteric plexuses, mucosa and muscular layers	[14,29,30] [31]
Cat	nerve fibers in the myenteric ganglia and muscle layers	[19]
Sheep	nerve fibers in the myenteric ganglia and muscle layers	[19,33]
Ferret	nerve fibers in the myenteric ganglia and muscle layers	[19]
Pancreas
Rat	endocrine parts of pancreas	[18]
Sheep	nerve fibers in the islet of Langerhans and small arteries neurons in the intrapancreatic ganglia	[32,33]