Effect of Noradrenaline on Smooth Muscle Strips from the Reticular Groove of Adult Cattle

Abstract

Summary The effect of noradrenaline (NA) on smooth muscle strips from the reticular groove of adult cattle was studied. The mechanical activity of the muscle strips was recorded isometrically. Noradrenaline caused concentration dependent (1.1 · 10−6 ‐ 55 · 10−6mol/l) contractions of both the transversal muscle strips from the floor and the longitudinal muscle strips from the lips of the reticular groove. This excitatory effect of noradrenaline was antagonized by the α‐receptor antagonist prazosine (10−8 mol/1) and by higher concentrations of the α2‐receptor antagonist yohimbine (10−6 mol/1) and atropine (10−5 mol/1). Tetrodotoxin (5 ·10−6 mol/1) and latrotoxin did not affect the contractile response of the muscle strips to noradrenaline (55 · 10−6 mol/l). Furthermore, strips stored for 24 hours in Tyrode's solution at 4 °C without oxygen supply maintained their full sensitivity to noradrenaline. Propranolol (10−4 mol/1), a β‐receptor antagonist, led to a significant increase of the contractions induced by noradrenaline (55 · 10−6 mol/l). These results suggest that noradrenaline increases the tone of the smooth muscle of the reticular groove via α‐adrenergic receptors and decreases its tone via β‐adrenergic receptors. Both receptor types are located on the smooth muscle cells. The α1‐receptor mediated effect appears to be predominant.

Differential effects of ω‐conotoxin GVIA and tetrodotoxin on vasoconstrictions evoked by electrical stimulation and nicotinic receptor stimulation in canine isolated, perfused splenic arteries

“…When a small increase in perfusion pressure elicited by 100 nmol nicotine returned to a base line, the second administration of 1 pmol ACh was injected immediately. The treatment with nicotine almost completely inhibited the vasoconstrictor response to ACh, but did not Figure 6 Vascular responses to acetylcholine (n = 6), noradrenaline (n = 3) and ATP (n = 4) before (0) and after (0) (Denac et al, 1991;Satake et al, 1992). Our present results provide further evidence in support of their observations.…”

An immunohistochemical study of the distribution of nitric oxide synthase-immunoreactive neurons and fibers in the reticular groove of suckling lambs

“…2003). Pharmaco‐physiological studies on the RG of calves have demonstrated that both nor‐adrenaline (Denac et al. 1991) and acetylcholine (Barahona et al.…”

“…There are only a few immunohistochemical studies referring to the ENS of the RG of bovines (Kitamura et al 1986(Kitamura et al , 1987Barahona et al 1997;Teixeira et al 1998) and sheep (Pfannkuche et al 2003). Pharmaco-physiological studies on the RG of calves have demonstrated that both nor-adrenaline (Denac et al 1991) and acetylcholine (Barahona et al 1997) play an essential role in the modulation of the activity and maintenance of muscle tone; in addition, a functional study involving esophageal groove strips revealed that NO plays a role in non-adrenergic non-cholinergic relaxation, which is significantly inhibited by incubation with L-NOARG, an inhibitor of NO synthesis (Barahona et al 1998).…”

Alimentação de bezerros ruminantes com dieta sólida ou líquida, via goteira esofageana: formação da goteira e escape ruminal

“…O reflexo pode, inclusive, ser mantido ou provocado no animal adulto, como provaram ∅rskov et al (1970a), trabalhando com bovinos, e Mikhail et al (1988), com caprinos. Algumas substâncias, como sulfato de cobre (Brugere et al, 1987), bicarbonato de sódio (Carruthers et al, 1994), vasopressina (Brugere et al, 1987Van WeerenKaverling Buisman et al, 1990a) e noradrenalina (Denac et al, 1991) estimulam a ocorrência do reflexo, tanto em animais jovens como em adultos.…”