Afferent vagal fibres and central cholinergic mechanisms are involved in the TRH-induced reversal of haemorrhagic shock.
In a model of haemorrhagic shock causing the death of all saline-treated rats within 25.8 +/- 2.7 min after treatment, the intravenous injection of thyrotropin-releasing hormone tartrate (TRH-T) at the dose of 4 mg/kg induces a prompt and sustained increase of arterial pressure and pulse amplitude, with survival of all rats. Bilateral vagotomy, atropine sulphate (2 mg/kg intraperitoneally) and hemicholinium-3 (20 micrograms/rat intracerebroventricularly) partially prevent the TRH-T-induced shock reversal, whereas atropine methylbromide has no effect. These data indicate that afferent vagal fibres, brain cholinergic neurons and central muscarinic receptors play a role in the mechanism of the anti-shock effect of TRH-T.
Vergoni
A V
AV
Institute of Pharmacology, University of Modena, Italy.
Marrama
D
D
Guarini
S
S
Tagliavini
S
S
Bazzani
C
C
Maugeri
A
A
Bertolini
A
A
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006426:Hemicholinium 3 / Q000494:pharmacology; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012771:Shock, Hemorrhagic / Q000188:drug therapy / Q000503:physiopathology*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D014628:Vagotomy; D014630:Vagus Nerve / Q000187:drug effects / Q000503:physiopathology*
D006426:Hemicholinium 3; D013973:Thyrotropin-Releasing Hormone; D001285:Atropine