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G Bertaccini - One of the best experts on this subject based on the ideXlab platform.

  • the bronchoconstrictor action of the tetradecapeptide bombesin in the guinea pig
    Journal of Pharmacy and Pharmacology, 2011
    Co-Authors: M Impicciatore, G Bertaccini
    Abstract:

    The tetradecapeptide bombesin was found to exert a potent spasmogenic action on the bronchiolar muscle of the anaesthetized guinea-pig. The threshold bronchoconstrictor dose ranged between 50 and 200 ng kg−1. Other spasmogenic substances tested in the same experimental conditions, except Physalaemin, were much less effective. Since antagonists of acetylcholine, histamine or 5-hydroxytryptamine did not inhibit the bronchoconstriction it is suggested that bombesin acts either by direct stimulation of the smooth muscle or by the prior release of other, as yet unidentified, spasmogenic substances.

  • enlargement of salivary glands in rats after chronic administration of Physalaemin or isoprenaline
    Journal of Pharmacy and Pharmacology, 2011
    Co-Authors: G Bertaccini, G. De Caro, R Cheli
    Abstract:

    Chronic administration of Physalaemin and isoprenaline to rats produced a significant salivary glands enlargement which was moderate (34% fresh weight increase and 48% dry weight increase compared with control glands) after the peptide administration and striking after the amine (630% fresh weight increase and 600% dry weight increase compared with control glands). Physalaemin caused only hypertrophy of the gland, whereas isoprenaline induced a marked hyperplasia.

R Cheli - One of the best experts on this subject based on the ideXlab platform.

G. De Caro - One of the best experts on this subject based on the ideXlab platform.

J L Henry - One of the best experts on this subject based on the ideXlab platform.

  • responses of functionally identified neurones in the dorsal horn of the cat spinal cord to substance p neurokinin a and Physalaemin
    Neuroscience, 1991
    Co-Authors: M W Salter, J L Henry
    Abstract:

    Abstract The mammalian tachykinins, substance P and neurokinin A, and the non-mammalian tachykinin, Physalaemin, were tested on functionally identified dorsal horn neurones in vivo . The experiments were done on cats which were anaesthetized with sodium pentobarbital or were anaemically decerebrated. Extracellular single-unit recordings were made in the lumbar spinal cord and the tachykinins were applied by iontophoresis. Each neurone was classified functionally as wide dynamic range, non-nociceptive, nociceptive specific or proprioceptive. The response to tachykinin application was determined for each neurone. Application of each of the tachykinins evoked a characteristic excitatory response which was delayed in onset, slow in developing and prolonged: Physalaemin excited 99/131 neurones tested, neurokinin A excited 45/63 neurones and substance P excited 32/49 neurones. With two neurones Physalaemin evoked a depression of the rate of firing, which may have been caused indirectly by excitation of a neighbouring neurone. Such depression was not elicited by either substance P or by neurokinin A. Physalaemin had a preferential excitatory effect on nociceptive neurones evoking excitation of 76/94 nociceptive neurones compared with 12/23 non-nociceptive neurones (χ 2 = 7.9, 1d.f., P = 0.005). Substance P also caused a preferential excitation, with 30/40 nociceptive neurones being excited while all of the non-nociceptive neurones ( n = 7) were unaffected (χ 2 = 11.5, 1d.f., P = 0.0007). In contrast, neurokinin A failed to have a preferential effect; 32/46 nociceptive and 9/10 non-nociceptive neurones were excited (χ 2 = 1.0, 1d.f., P = 0.40). Comparing the proportions of nociceptive neurones excited by the different tachykinins indicated that this type of neurone was not differently sensitive to any of the three peptides (χ 2 = 3.2, 2 d.f., P = 0.20). On the other hand, non-nociceptive neurones were preferentially excited by neurokinin A and Physalaemin compared with substance P (χ 2 = 13.4, 2 d.f., P = 0.001). With regard to the endogenous tachykinins the results of this study may be interpreted in the following ways. The differential excitatory effect of substance P on nociceptive neurones supports the proposed role for this peptide in the transmission specifically of nociceptive inputs at the first afferent synapse. On the other hand, as neurokinin A excited non-nociceptive as well as nociceptive neurones, there may be a functional role for neurokinin A distinct from that of substance P.

Yasutake Shimizu - One of the best experts on this subject based on the ideXlab platform.

  • contractile responses induced by Physalaemin an analogue of substance p in the rat esophagus
    European Journal of Pharmacology, 2010
    Co-Authors: Takahiko Shiina, Takeshi Shima, Haruko Hirayama, Hirofumi Kuramoto, Tadashi Takewaki, Yasutake Shimizu
    Abstract:

    We examined the effects of Physalaemin, an agonist of tachykinin receptors, on mechanical responses in the rat esophagus to clarify possible regulatory roles of tachykinins in esophageal motility. Exogenous application of Physalaemin caused tonic contractions in rat esophageal segments when tension was recorded in the longitudinal direction but not when tension was recorded in the circular direction. The Physalaemin-evoked contractions were blocked by pretreatment with nifedipine, a blocker of L-type calcium channels in both striated and smooth muscle cells. However, tetrodotoxin, a blocker of voltage-dependent sodium channels in striated muscle cells and neurons, did not affect the Physalaemin-induced contractions. These results indicate that Physalaemin might induce contractile responses in longitudinal smooth muscle of the muscularis mucosa via direct actions on muscle cells but not on neurons. Although pretreatment with a tachykinin NK1 receptor antagonist, N-acetyl-l-tryptophan 3,5-bis (trifluoromethyl) benzyl ester (L-732,138), did not significantly affect the Physalaemin-evoked contractions in rat esophageal segments, a tachykinin NK2 receptor antagonist, (S)-N-methyl-N[4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl) butyl] benzamide (SR48968), and a tachykinin NK3 receptor antagonist, (S)-(N)-(1-(3-(1-benzoyl-3-(3,4-dichlorophenyl) piperidin-3-yl)propyl)-4-phenylpiperidin-4-yl)-N-methylacetamide (SR142801), significantly inhibited the Physalaemin-evoked contractions. These results suggest that tachykinins can activate longitudinal contraction of smooth muscle in the muscularis mucosa, mediated via tachykinin NK2 and NK3 receptors on muscle cells, in the rat esophagus.