SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Fregoneze,J.B.; Luz,C.P.; Castro,L.; Oliveira,P.; Lima,A.K.S.; Souza,F.; Maldonado,I.; Macêdo,D.F.; Ferreira,M.G.; Bandeira,I.P.V.; Rocha Jr.,M.A.; Carvalho,F.L.Q.; De-Castro-e-Silva,E..

We have demonstrated that central administration of zinc in minute amounts induces a significant antidipsogenic action in dehydrated rats as well as in rats under central cholinergic and angiotensinergic stimulation. Here we show that acute third ventricle injections of zinc also block water intake induced by central ß-adrenergic stimulation in Wistar rats (190-250 g). Central inhibition of opioid pathways by naloxone reverses the zinc-induced antidipsogenic effect in dehydrated rats. After 120 min, rats receiving third ventricle injections of isoproterenol (160 nmol/rat) exhibited a significant increase in water intake (5.78 ± 0.54 ml/100 g body weight) compared to saline-treated controls (0.15 ± 0.07 ml/100 g body weight). Pretreatment with zinc (3.0,...

Anti-hyperalgesic effect of electroacupuncture in a model of post-incisional pain in rats

Palavras-chave: Zinc; Isoproterenol; Opioids; Thirst; Naloxone; Rats.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001000007

Oliveira,R.; Prado,W.A..

Electroacupuncture has been proposed to be a low cost and practical method that allows effective pain management with minimal collateral effects. In this study we have examined the effect of electroacupuncture against the hyperalgesia developed in a model of post-incisional pain in rats. A 1-cm longitudinal incision was made through the skin and fascia of the plantar region of the animal hind paw. Mechanical hyperalgesia in the incision was evaluated 135 min after the surgery with von Frey filaments. The tension threshold was reduced from 75 g (upper limit of the test) to 1.36 ± 0.36 g (mean ± SEM) in control rats. It is shown that a 15-min period of electroacupuncture applied 120 min after surgery to the Zusanli (ST36) and Sanyinjiao (SP6) points, but not...

Endogenous opiate analgesia induced by tonic immobility in guinea pigs

Palavras-chave: Electroacupuncture; Post-incisional pain; Hyperalgesia; Naloxone.

Ano: 2000

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000800012

Leite-Panissi,C.R.A.; Rodrigues,C.L.; Brentegani,M.R.; Menescal-de-Oliveira,L..

A function of the endogenous analgesic system is to prevent recuperative behaviors generated by tissue damage, thus preventing the emission of species-specific defensive behaviors. Activation of intrinsic nociception is fundamental for the maintenance of the behavioral strategy adopted. Tonic immobility (TI) is an inborn defensive behavior characterized by a temporary state of profound and reversible motor inhibition elicited by some forms of physical restraint. We studied the effect of TI behavior on nociception produced by the formalin and hot-plate tests in guinea pigs. The induction of TI produced a significant decrease in the number of flinches (18 ± 6 and 2 ± 1 in phases 1 and 2) and lickings (6 ± 2 and 1 ± 1 in phases 1 and 2) in the formalin test...

Cholinergic-opioidergic interaction in the central amygdala induces antinociception in the guinea pig

Palavras-chave: Tonic immobility; Guinea pig; Antinociception; Opioids; Naloxone; Analgesia.

Ano: 2001

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000200013

Leite-Panissi,C.R.A.; Brentegani,M.R.; Menescal-de-Oliveira,L..

Several studies have demonstrated the involvement of the central nucleus of the amygdala (CEA) in the modulation of defensive behavior and in antinociceptive regulation. In a previous study, we demonstrated the existence of a cholinergic-opioidergic interaction in the CEA, modulating the defensive response of tonic immobility in guinea pigs. In the present study, we investigated a similar interaction in the CEA, but now involved in the regulation of the nociceptive response. Microinjection of carbachol (2.7 nmol) and morphine (2.2 nmol) into the CEA promoted antinociception up to 45 min after microinjection in guinea pigs as determined by a decrease in the vocalization index in the vocalization test. This test consists of the application of a peripheral...

A pyrazolyl-thiazole derivative causes antinociception in mice

Palavras-chave: Antinociception; Vocalization test; Cholinergic-opioidergic interaction; Amygdala; Naloxone; Atropine.

Ano: 2004

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004001000018

Prokopp,C.R.; Rubin,M.A.; Sauzem,P.D.; de Souza,A.H.; Berlese,D.B.; Lourega,R.V.; Muniz,M.N.; Bonacorso,H.G.; Zanatta,N.; Martins,M.A.P.; Mello,C.F..

The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1 H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 µmol/kg, sc) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 ± 6.15; B50 (8 µmol/kg): 16.92 ± 3.84; B50 (23 µmol/kg): 13.85 ± 3.84; B50 (80 µmol/kg): 9.54 ± 3.08; data are reported as means ± SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 µmol/kg, sc) prevented B50-induced...

The terrestrial Gastropoda Megalobulimus abbreviatus as a useful model for nociceptive experiments: effects of morphine and naloxone on thermal avoidance behavior

Palavras-chave: Antinociception; Pyrazolyl-thiazole derivatives; Writhing test; Opioid mechanism; Naloxone.

Ano: 2006

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000600013

Achaval,M.; Penha,M.A.P.; Swarowsky,A.; Rigon,P.; Xavier,L.L.; Viola,G.G.; Zancan,D.M..

We describe the behavior of the snail Megalobulimus abbreviatus upon receiving thermal stimuli and the effects of pretreatment with morphine and naloxone on behavior after a thermal stimulus, in order to establish a useful model for nociceptive experiments. Snails submitted to non-functional (22ºC) and non-thermal hot-plate stress (30ºC) only displayed exploratory behavior. However, the animals submitted to a thermal stimulus (50ºC) displayed biphasic avoidance behavior. Latency was measured from the time the animal was placed on the hot plate to the time when the animal lifted the head-foot complex 1 cm from the substrate, indicating aversive thermal behavior. Other animals were pretreated with morphine (5, 10, 20 mg/kg) or naloxone (2.5, 5.0, 7.5 mg/kg)...

Effect of naloxone on food competition aggression in food-restricted high and low aggression pigeons (Columba livia)

Palavras-chave: Snail; Thermal avoidance; Nociception; Morphine; Naloxone.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000100012

Fachinelli,C.; Torrecillas,M.; Rodríguez Echandía,E.L..

We determined the effect of the opiate receptor antagonist naloxone on aggression, emotion, feeder control, and eating behavior in high and low aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions. Pigeons were divided into pairs by previously ranked high aggression (total time spent in offensive aggression exceeding 60 s/5 min; N = 6 pairs) and low aggression females (time spent in offensive aggression less than 10 s/5 min; N = 6 pairs). A pigeon in each pair received an sc dose of naloxone (1 mg kg-1 ml saline-1) and the other animal received the vehicle. Trials (10 min) were performed 30 min after the naloxone/vehicle administration. The naloxone group of high aggression pigeons showed lower...

Sucrose ingestion causes opioid analgesia

Palavras-chave: Naloxone; Aggressive behavior; Emotional behavior; Food competition; Pigeons.

Ano: 2004

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000300010

Segato,F.N.; Castro-Souza,C.; Segato,E.N.; Morato,S.; Coimbra,N.C..

The intake of saccharin solutions for relatively long periods of time causes analgesia in rats, as measured in the hot-plate test, an experimental procedure involving supraspinal components. In order to investigate the effects of sweet substance intake on pain modulation using a different model, male albino Wistar rats weighing 180-200 g received either tap water or sucrose solutions (250 g/l) for 1 day or 14 days as their only source of liquid. Each rat consumed an average of 15.6 g sucrose/day. Their tail withdrawal latencies in the tail-flick test (probably a spinal reflex) were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after treatment. The indexes (mean ± SEM, N =...