Role of Histamine, Substance P and Slow-Reacting Substance of Anaphylaxis (Srs-A) in the Schultz-Dale Reaction of the Guinea-Pig Ileum

We examined the role of substance P (SP) and neurokinin A (NKA) in the postmortem bronchoconstriction in guinea pig lungs using isolated lungs superfused via the trachea. Airway opening pressure (Pao) during superfusion was monitored and the superfusate collected for analysis of SP- and NKA-like immunoreactivities (SP-LI and NKA-LI, respectively). Peak Pao (39.0 +/- 3.9 cmH2O) was reached 10 min after starting superfusion; Pao decreased slowly thereafter, reaching only 9.9 +/- 2.2% of the peak value 2 h after starting superfusion (P less than 0.005); 12.6 +/- 2.6 and 34.0 +/- 9.7 fmol of SP-LI and NKA-LI, respectively, were found in the fraction corresponding to 10-20 min of superfusion. Recovered immunoreactivities decreased to 5.2 +/- 0.3 and 9.3 +/- 1.8 fmol of SP-LI and NKA-LI, respectively, in the fraction corresponding to 110-120 min of superfusion (P less than 0.05). Inhibition of neutral endopeptidase with thiorphan resulted in significantly greater increases in Pao (P less than 0.005) and augmentation of the recovery of SP-LI and NKA-LI (P less than 0.05 and P less than 0.001, respectively). Capsaicin treatment of animals 7-10 days before the removal of their lungs abolished the increase in Pao during superfusion and resulted in a significant decrease in the amount of SP-LI and NKA-LI recovered. Our data confirm that tachykinin release occurs during postmortem bronchoconstriction in guinea pig lungs and, furthermore, that tachykinin degradation by NEP modulates the intensity of this response.

Download Full-text

POSSIBLE ROLE OF PROSTAGLANDINS (PG's) IN THE EFFECT OF THE SYMPATHETIC SYSTEM ON THE PARASYMPATHETIC SYSTEM IN THE GUINEA-PIG ILEUM

Abstracts ◽

10.1016/b978-0-08-023768-8.51617-0 ◽

1978 ◽

pp. 626

Author(s):

O. Kadlec ◽

K. Mašek ◽

I. Šeferna

Keyword(s):

Guinea Pig ◽

Sympathetic System ◽

Guinea Pig Ileum ◽

Parasympathetic System

Download Full-text

Somatostatin modulation of peptide-induced acetylcholine release in guinea pig ileum

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1984.246.5.g509 ◽

1984 ◽

Vol 246 (5) ◽

pp. G509-G514 ◽

Cited By ~ 5

Author(s):

D. H. Teitelbaum ◽

T. M. O'Dorisio ◽

W. E. Perkins ◽

T. S. Gaginella

Keyword(s):

Substance P ◽

Guinea Pig ◽

Myenteric Plexus ◽

Acetylcholine Release ◽

Longitudinal Muscle ◽

Guinea Pig Ileum ◽

Gut Motility ◽

Release Of Acetylcholine

The peptides caerulein, neurotensin, somatostatin, and substance P modulate the activity of intestinal neurons and alter gut motility. We examined the effects of these peptides on acetylcholine release from the myenteric plexus and intestinal contractility in vitro. Caerulein (1 X 10(-9) M), neurotensin (1.5 X 10(-6) M), and substance P (1 X 10(-7) M) significantly enhanced the release of [3H]acetylcholine from the myenteric plexus of the guinea pig ileum. This effect was inhibited by tetrodotoxin (1.6 X 10(-6) M). Somatostatin (10(-6) M) inhibited caerulein- and neurotensin-evoked release of acetylcholine but did not inhibit release induced by substance P. Caerulein, neurotensin, and substance P caused contraction of the guinea pig ileal longitudinal muscle. Somatostatin inhibited the contractions induced by caerulein and neurotensin. In contrast, substance P-induced contraction was not inhibited significantly by somatostatin. Thus, in the guinea pig ileum, caerulein-, neurotensin-, and substance P-induced contractility is due, at least in part, to acetylcholine release from the myenteric plexus. The ability of somatostatin to inhibit peptide-induced contractility is selective, and its mechanism may be attributed to inhibition of acetylcholine release.

Download Full-text