Effects of acute or chronic administration of low doses of a dopamine agonist on drinking and locomotor activity in the rat

Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively. We found that acute administration of 8-OH-DPAT increased locomotor activity and pain thresholds in the sham rats but had no effect on the OB rats. In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level. Increased pain thresholds were also observed in the sham rats after the chronic administration. These results demonstrated that chronic administration of 8-OH-DPAT reversed the depression-induced decrease in pain sensitivity in rats, suggesting that 5-HT1A receptor may play a role in the depression-associated hypoalgesia.

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Chronic administration of l-sulpiride at low doses reduces A10 but not A9 somatodentritic dopamine autoreceptor sensitivity

European Journal of Pharmacology ◽

10.1016/0014-2999(96)00581-x ◽

1996 ◽

Vol 312 (2) ◽

pp. 179-181 ◽

Cited By ~ 2

Author(s):

Marco Diana ◽

Anna Lisa Muntoni ◽

Marco Pistis ◽

Maria Collu ◽

Angelo Forgione ◽

...

Keyword(s):

Chronic Administration ◽

Low Doses ◽

Dopamine Autoreceptor

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Behavioural multigenerational effects induced by the administration of very low doses of zinc during pregnancy, lactation, and prepuberal period in the rat

Journal of Neurorestoratology ◽

10.26599/jnr.2021.9040004 ◽

2021 ◽

Vol 9 (1) ◽

pp. 72-80

Author(s):

Silvia G. Ratti ◽

Osvaldo J. Sacchi ◽

Edgardo O. Alvarez

Keyword(s):

Social Activity ◽

Behavioral Responses ◽

Chronic Administration ◽

Female Rats ◽

Male Rats ◽

Experimental Setup ◽

Low Doses ◽

Next Generation ◽

Intergenerational Effect ◽

Multigenerational Effects

In studies from this laboratory, the chronic administration of ZnTe during pregnancy, lactation, and prepuberal stages of litter (F1 generation) modified the behavioral patterns of motivated exploration, lateralized exploration, social activity, and survival responses of maturing rats. To determine whether these affected behaviors would extend to the next generation, F1 litter rats previously exposed to tellurium (Te) up to 30-day-old were left at rest with no further treatment up to 90-day-old. Then, F1 female rats were mated with normal untreated male rats, and in the next generation (F2), the litter rats at 30-day-old preserved the modified behaviors previously observed in their parents. The study revealed that Te effects were intergenerational. Here, considering that ZnTe was used in the previous study and that Zn ion has many physiological functions in the cell, experiments were conducted to elucidate if Zn would have an intergenerational effect similar to Te. Working with the same experimental setup as in the previous study but using ZnCl2 instead of ZnTe, results revealed that none of the behavioral responses studied were affected by the F1 generation. However, in the F2 generation, lateralized exploration and survival behavior were inhibited, suggesting that Zn also has an intergenerational effect.

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