Occurrence, Distribution and Motor Effects of Galanin in the Porcine Lower Esophageal Sphincter

Abstract

Specimens from the lower esophageal sphincter (LES) region of the pig were analyzed for galanin-like immunoreactivity (GAL-LI) using radioimmunoassay and immuno histochemistry. The mean concentration of GAL-LI was 3.4 pmol/g tissue. GAL-LI nerve fibers were observed surrounding muscle bundles in the smooth circular muscle layer, and in ganglion cells of the myenteric plexus. Bolus injection of 40–200 pmol/kg of galanin directly into the arterial supply of the resting LES increased the LES pressure (LESP) dose-depen-dently, whereas slow infusion of 2–100 pmol galanin/kg/min had no effect on resting LESP. The vagally increased LESP was not modulated by simultaneous galanin infusion, and the concentration of galanin in the venous effluent of the LES declined insignificantly during vagal stimulation. It is concluded that galanin may be an important neuropeptide for the modulation of resting LES tone.

Role of Galanin in the Gastrointestinal Sphincters a

“…Effects and Mechanisms of Actions of Galanin. The effect of galanin on the LES has been studied in the opossum, 11 pig, 12 and cat. 13 In the opossum and pig, galanin was very potent in causing contractions of the LES due to its direct action on smooth muscle, because this effect was not modified by different neurohumoral antagonists (atropine, phentolamine, methysergide, pyrilamine, and indomethacin) and the neurotoxin tetrodotoxin.…”

“…Interestingly, galanin (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) caused an increase in resting IAS tension by direct action at the smooth muscle, and it had no significant effect on neurally mediated IAS relaxation. The middle portion of galanin (7)(8)(9)(10)(11)(12)(13)(14)(15)(16) had no significant effect on the IAS. It was interesting that although the relaxant actions of galanin reside in the NH 2 -terminal, a whole molecule of galanin is required for the full effect, suggesting indirectly the importance of the COOH-terminal in the relaxation response.…”

“…Galanin is present in porcine, 12 human, 60 canine, 22 feline, 13 rat, 5 mouse, 5 and opossum 61 esophagus and LES. Galanin-like immunoreactivity has been observed in nerve cell bodies of the myenteric plexus and in nerve fibers along the smooth muscle bundles.…”

Galanin and Vasoactive Intestinal Polypeptide: Coexistence and Corelease from the Vascularly Perfused Pig Ileum during Distension and Chemical Stimulation of the Mucosa

“…GAL and VIP Radioimmunoassay GAL antisera were raised in rabbits as previously described [11]. GAL was labelled with l25I according to the stoichiometric chloramine T-mcthod [12] and purified by high pressure liquid chromatography on a Vydac C-18 column (No.…”

Galanin: Distribution and Effect on Contractile Activity and Release of Vasoactive Intestinal Polypeptide from the Isolated Perfused Porcine Ileum

“…Hence the tissue was perfused with 4% paraformaldehyde in 0.1 M sodium phosphate, pH 7.4 for 10 min. Speci mens from the mid ileum were removed and postfixed in the same solution for 24 h. The further processing of tissue and production of antiserum against GAL has been reported in details previously [12].…”