Is there an opiate receptor in the snail Megalobulimus sanctipauli? Action of morphine and naloxone

Romero, Sônia Maria Brazil; Hoffmann, Anette; Menescal-de-Oliveira, Leda

doi:10.1016/1367-8280(94)90007-8

Cited by 8 publications

(15 citation statements)

References 21 publications

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“…The snails showed exploratory behavior at ambient temperature (22ºC) or non-thermal stress (30ºC), but a stereotyped behavior at 50ºC. These results were similar to those obtained with other species of gastropods (4,7).…”

Section: Discussionsupporting

confidence: 78%

“…Moreover, the administration of morphine sulfate, methionine-enkephalin or ß-endorphin resulted in a significant increase in the latency of thermal avoidance behavior (4,6). Also, the increased latency resulting from morphine administration to C. nemoralis, Limax maximus and M. sanctipauli after a thermal stimulus can be suppressed by the opiate antagonist, naloxone (3,4,7).…”

Section: Introductionmentioning

confidence: 89%

“…The animals were kept in a screened terrarium, subjected to normal annual light and temperature variations, and fed lettuce and water ad libitum. To minimize the novelty stress (4,9,14), the satiated snails were allowed to rehydrate in individual humid chambers 2 h prior to the experiments. Pharmacological agents were dissolved in saline and injected into the intrahemocelic cavity through the anterior ventral zone of the foot.…”

Section: Animalsmentioning

confidence: 99%

“…Also, the increased latency resulting from morphine administration to C. nemoralis, Limax maximus and M. sanctipauli after a thermal stimulus can be suppressed by the opiate antagonist, naloxone (3,4,7). Thus, in these gastropods the ability of the nonselective opiate antagonist naloxone to produce a complete blockade of morphine analgesia indicates that a µ receptor is related to this behavior (4,8). Naloxone alone decreases the latency of the thermal stress (2).…”

Section: Introductionmentioning

confidence: 99%

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

Achaval

Penha

Swarowsky

et al. 2005

Braz J Med Biol Res

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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) 15 min prior to receiving a thermal stimulus (50ºC; N = 9 in each group). The results (means ± SD) showed an extremely significant difference in response latency between the group treated with 20 mg/kg morphine (63.18 ± 14.47 s) and the other experimental groups (P < 0.001). With 2.5 mg/kg (16.26 ± 3.19 s), 5.0 mg/kg (11.53 ± 1.64 s) and 7.5 mg/kg naloxone (7.38 ± 1.6 s), there was a significant, not dose-dependent decrease in latency compared to the control (33.44 ± 8.53 s) and saline groups (29.1 ± 9.91 s). No statistically significant difference was found between the naloxone-treated groups. With naloxone plus morphine, there was a significant decrease in latency when compared to all other groups (minimum 64% in the saline group and maximum 83.2% decrease in the morphine group). These results provide evidence of the involvement of endogenous opioid peptides in the control of thermal withdrawal behavior in this snail, and reveal a stereotyped and reproducible avoidance behavior for this snail species, which could be studied in other pharmacological and neurophysiological studies.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 89%

Section: Animalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Achaval

Penha

Swarowsky

et al. 2005

Braz J Med Biol Res

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“…Several aspects of the defense reaction evoked by a novel (innocuous or noxious) stimulus have been studied in various gastropod species by a number of investigators (5,(7)(8)(9)(10). Although the pathways which control defensive behaviors often share circuitry with cardiovascular function (11,12), the literature concerning the heart rate alterations associated with these behaviors is limited.…”

mentioning

confidence: 99%

Role of the cardiac nerve in the effect of a novel innocuous stimulus on the heart rate of Megalobulimus mogianensis

Romero

Hoffmann

2006

Braz J Med Biol Res

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The effects of a brief jet of water delivered to the anterior portion of body-head on the heart rate of Megalobulimus mogianensis were determined in a group of intact snails (N = 8), previously prepared for electrocardiogram recording. The heart rate was significantly increased following stimulation. Nevertheless, with repetition of the stimulus there was a significant decrease in the magnitude of the heart rate variation and in the time for the basal heart rate to recover (first stimulus, 7.4 ± 1.2 bpm and 15.5 ± 1.8 min; second stimulus, 4.8 ± 1.0 bpm and 10.6 ± 1.5 min; third stimulus, 5.0 ± 0.3 bpm and 11.1 ± 1.8 min), indicating that this behavioral response undergoes early habituation. To determine the role of the cardiac nerve in mediating the heart rate alterations induced by the jet of water two other groups were tested: denervated animals (N = 8) and sham-operated control animals (N = 8). Although the innocuous stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (3.2 ± 0.4 bpm) was 41% of the value obtained in sham-operated animals (7.8 ± 1.5 bpm), indicating that the cardiac nerve is responsible for 59% of the cardioacceleration induced by the innocuous stimulus. The increase in heart rate observed in denervated animals may be due to an increase in venous return promoted by the intense muscular activity associated with the retraction-protraction of the anterior part of the body induced by the jet of water. Correspondence

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NADPH-diaphorase activity in the nociceptive pathways of land snail Megalobulimus abbreviatus: the involvement of pedal ganglia

et al. 2009

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NADPH-diaphorase (NADPH-d) is a histochemical marker for nitric oxide synthase (NOS), widely used to identify nitric oxide (NO) producing cells in the nervous system of both vertebrates and invertebrates. Using NADPH-d histochemistry and semi-quantitative optical densitometry, we characterized the NO-producing neurons in the pedal ganglia of young and adult Megalobulimus abbreviatus, subjected to aversive thermal stimulus. The animals were killed at different times (3, 6, 12 and 24 h) following stimulus. The enzymatic activity was detected in different cellular subsets and neuronal processes. In all the studied pedal ganglia subregions, the optical density of positive neurons (P < 0.05) and neuropilar area 1 (P < 0.01) was significantly different in treated animals when compared to controls. The increase in nitrergic activity induced by nociceptive stimulus suggests the involvement of NO in the nociceptive circuit of M. abbreviatus, which is well maintained throughout evolution, and could be helpful in drawing cellular homologies with other gastropods.

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Is there an opiate receptor in the snail Megalobulimus sanctipauli? Action of morphine and naloxone

Cited by 8 publications

References 21 publications

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

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

Role of the cardiac nerve in the effect of a novel innocuous stimulus on the heart rate of Megalobulimus mogianensis

NADPH-diaphorase activity in the nociceptive pathways of land snail Megalobulimus abbreviatus: the involvement of pedal ganglia

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