Automated computerized rat eater meter: Description and application

Meguid, Michael M.; Kawashima, Yoshito; Campos, Antônio Carlos Ligocki; Gelling, Paul D.; Hill, Thomas; Chen, Ting‐Yuan; Yang, Zhong-Jin; Hitch, David C.; Hammond, William G.; Mueller, William J.

doi:10.1016/0031-9384(90)90222-p

Cited by 61 publications

(20 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Before the operation for cannula placement, the rats were acclimated to the Automated Computerized Rat Eater Meter (ACREM) cages (23). Their daily FI and each MZ and MN were measured for 1 wk.…”

Section: Methodsmentioning

confidence: 99%

Expression of dopaminergic receptors in the hypothalamus of lean and obese Zucker rats and food intake

Fetissov

Meguid

Sato

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

102

View full text Add to dashboard Cite

As revealed by previous microdialysis studies, basal and food intake-accompanied dopamine release significantly differs in the hypothalamus of obese vs. lean Zucker rats. In the present study, we determined whether dopaminergic receptors are also compromised in obesity. Dopaminergic D(1) and D(2) receptor mRNA expression was studied in the ventromedial hypothalamus (VMH), lateral hypothalamic area (LHA), and the adenohypophysis (AH) of obese and lean Zucker rats using RT-PCR technique. In obese Zucker rats, we found an upregulation of D(1) receptor mRNA in the VMH and AH and a downregulation in the LHA, whereas D(2) receptor mRNA was downregulated in both the VMH and LHA, but not changed in the AH, compared with lean rats. Also, an increase of D(1) receptor staining was seen in the paraventricular nucleus of obese rats by immunohistochemistry. We selected the VMH to test if the observed changes in the dopamine receptor expression of obese rats induce behavioral sensitization to dopamine as expressed by hyperphagia. The overnight food-deprived rats received a single VMH injection (10 nmol) of sulpiride (D(2) receptor antagonist) or saline as control, then food was provided and 1-h food intake was measured. Food intake after sulpiride vs. saline injection was greater in obese rats but was not different in lean rats. Our data suggest that downregulation of D(2) receptor in the hypothalamus at least in the VMH induces behavior sensitization for having large meals. Low D(2) receptor expression may be causal for an exaggerated dopamine release observed in obese rats during food ingestion and for reduced satiety feedback effect of dopamine. High level of D(1) receptor expression in the VMH and low in the LHA may also contribute to the specific feeding pattern in obese rats represented by large meal size and low meal number.

show abstract

Section: Methodsmentioning

confidence: 99%

Expression of dopaminergic receptors in the hypothalamus of lean and obese Zucker rats and food intake

Fetissov

Meguid

Sato

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

102

View full text Add to dashboard Cite

show abstract

“…13 It continuously measures the feeding indexes of meal size, meal number, as well as food intake for both dark and light cycles and for 24 h. Rats were studied in ACREM equipped cages for 2 weeks beginning 2 months after transplantation. Body weight of the rats was measured every 4 days.…”

Section: Measurement Of Food Intake Meal Size and Meal Numbermentioning

confidence: 99%

VMN dopaminergic graft and feeding pattern in obese Zucker rats

Fetissov¹,

Meguid²,

Miyata³

et al. 2000

Int J Obes

View full text Add to dashboard Cite

OBJECTIVE: To study the role of dopamine in the ventromedial hypothalamus (VMN) in the regulation of meal size and meal number during obesity. METHODS: Embryonic mesencephalic cells rich in dopaminergic neurons from lean rats were grafted into the VMN of obese Zucker rats. Since food intake is the product of meal size and number, these variables were measured using a rat`eater meter'. Dopamine and serotonin concentrations in the VMN were assayed in grafted and control rats via in vivo microdialysis and HPLC two months after transplantation. RESULTS: Food intake increased in grafted rats due to an increase of both meal size and meal number 2 weeks after implantation and to an increase of meal size with insuf®cient compensatory decrease of meal number 2 months after transplantation. Grafted rats showed higher absolute dopamine and lower serotonin concentrations in the VMN. CONCLUSION: It would appear that an increase of dopamine and a decrease of serotonin in the VMN of grafted obese rats may correlate with increase in meal number and meal size, respectively. Since obese Zucker rats usually display an enlarged meal size, we deduce from the data that chronically elevated VMN dopamine and low serotonin are involved in producing the large meal size observed during obesity.

show abstract

“…Food intake, meal size, and meal number were measured continuously with the help of an ACREM whose design, function, and utility were previously described in detail [24]. Briefly, the ACREM consists of commercially available metabolic cages in which the supplied feeding cup has been replaced by an electronic scale balance and two photoelectric cells centered above the food dish which includes both the food cup and a spillage collector bowl.…”

Section: Automated Computerized Rat Eater Meter (Acrem)mentioning

confidence: 99%

“…The signals generated are processed, interpreted, and stored by a computer. As determined in the original studies [24], a meal is defined as a bite or a series of bites preceded and followed by at least 5 min of feeding inactivity. Measurements made were food intake (FI), defined as the amount of food consumed in grams per study period (either per 24 h or per 12-h light-dark cycle); meal number (MN), defined as the total number of meals per study period; and meal size (MZ), defined as the total amount of food consumed in grams per meal in each study period.…”

Section: Automated Computerized Rat Eater Meter (Acrem)mentioning

confidence: 99%

“…Since short-term satiety is determined by the factors governing when the meal should stop, and long-term satiety by factors governing when the meal should start, we have updated Pankepp's hypothesis by proposing that LHA influences MZ and VMN influences MN [22]. By use of the in vivo brain microdialysis technique and of the automated computerized rat eater meter [24], we focused our studies on the activity of these brain areas. Specifically, we measured the intra-VMN and intra-LHA levels of serotonin and dopamine (well-established neurotransmitters involved in the hypothalamic control of food intake), as they relate to the control of MN and MZ.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation