Identification of histaminic (H1-type) receptors in small intestine of broilers by application of histamine and some of its agonists and antagonists

Abstract

Histamine is a biologically active amine (biogenic amine) that has a broad spectra of physiologic and pathologic reactions in the organism. Its effects are shown through 4 types of specific receptors (H1, H2, H3 and H4). Histamine is one of the main causes of intestine disorders and the occurrence of diarrhea, both of which are very common in broilers. Whilst there is no information in scientific literature about the presence of histaminic receptors in smooth muscles of the small intestine wall of broilers (duodenum, jejunum and ileum), we tried to determine their presence, distribution and type in this kind of muscles. Investigations were carried out on isolated smooth muscles of the circular and longitudinal layer of the broiler small intestine (strip dimension 3-4 mm x 2 cm). The muscle strip was then placed in an isolated organ bath and the contractions obtained were registered with isometric transducers on a two-channel printer. This was done following the addition of histamine, betahistine (H1 agonist), and mepiramine (H1 antagonist). Muscle vitality was checked by adding acethylcholine chloride. Using the obtained results, it can be concluded that H1 types of histaminergic receptors are present in smooth muscles of the small intestine of broilers. .

Histamin je biološki aktivni amin (biogeni amin) koji ima širok spektar fizioloških i patoloških delovanja u organizmu. Svoje delovanje ispoljava preko četiri tipa specifičnih receptora (H1, H2, H3i H4). Histamin je jedan od glavnih uzroka poremećaja funkcije creva i nastanka proliva, koji su kod brojlera česti. Pošto u stručnoj literaturi nema podataka o zastupljenosti histaminskih receptora u glatkoj muskulaturi zida tankog creva (duodenuma, jejunuma i ileuma) brojlera, pokušali smo utvrditi njihovu zastupljenost, distribuciju i vrstu u ovoj muskulaturi. Ispitivanja su vršena na izoliranoj glatkoj muskulaturi cirkularnog i longitudinalnog sloja sva tri dela tankog creva brojlera (strip dimenzija 3-4 mm x 2 cm). Mišićni strip je postavljen u kupatilo za izolirane organe, a izazvane kontrakcije su registrovane na dvokanalnom pisaču izometrijskim transdjuserima, nakon dodavanja histamina, betahistina (H1 agonist) i mepiramina (H1 antagonist). Vitalnost glatke muskulature tankog creva brojlera smo proveravali dodavanjem acetilholina. Na osnovu dobijenih rezultata se može zaključiti da su histaminergični receptori H1 tipa zastupljeni u glatkoj muskulaturi sva tri segmenta tankog creva brojlera.