Galanin: neuromodulatory and direct contractile effects on smooth muscle preparations.
The effects of galanin, a newly isolated neuropeptide, and of a galanin fragment (galanin 1-10) were studied on various smooth muscle preparations in vitro. Direct motor effects as well as effects on electrically induced (neuronally mediated) responses (neuromodulatory effects) were observed. Both gatanin and galanin 1-10 evoked a strong contractile response in rat jejunal longitudinal muscle. This effect was a direct one on the smooth muscle. Addition of galanin to guinea-pig taenia coli inhibited the contractile response to electrical stimulation, mediated by endogenous substance P and acetylcholine. In the rabbit iris sphincter, galanin reduced the acetylcholine-mediated but not the substance P-mediated contraction evoked by electrical stimulation. The neuromodulatory effects seem to be presynaptic and require the whole or possibly only the C-terminal part of the galanin molecule, since galanin 1-10 was ineffective. Rabbit femoral artery and vein, gastroepiploic and basilar arteries and guinea-pig trachea and main bronchi did not respond to either galanin or galanin 1-10.
E
E
Ekblad
R
R
Håkanson
F
F
Sundler
C
C
Wahlestedt
D000818:Animals; D003106:Colon / Q000187:drug effects; D005260:Female; D019004:Galanin; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007498:Iris / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects
D010446:Peptide Fragments; D010455:Peptides; D013373:Substance P; D013779:Tetrodotoxin; D019004:Galanin