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Changes in blood pressure and heart rate following dietary-induced thiamine deficiency in muricide rats
1Department of Pharmacology, Tohoku University School of Dentistry, Sendai, Japan.
Abstract:
The purpose of this study was to further investigate the effects of thiamine deficiency on blood pressure and heart rate in connection with muricide in rats. The rats, maintained on a thiamine-deficient diet, showed mouse-killing response (muricide). The incidence of muricide was 72% on day 30. In this period, marked decreases in body weight, heart rate and blood pressure were observed in thiamine-deficient rats. The changes of body weight and blood pressure were statistically different from pair-fed and control groups. In thiamine-deficient group, blood pressure of thiamine-deficient killer rats was lower than that of thiamine-deficient non-killer rats. It is noteworthy that recovery of bradycardia and hypotension was observed in thiamine-deficient rats after providing them with enough thiamine, but muricide was not recovered. Thus, it is unlikely that there is a direct correlation between muricide and the disturbance of cardiovascular system in thiamine-deficient killer rats. The present findings showed that muricide induced by thiamine deficiency has different physiological bases from the other types of muricide, i.e., olfactory bulb-lesioned muricide.
Insights
Thiamine deficiency in rats caused mouse-killing behavior (muricide) and cardiovascular changes. Muricide persisted even after thiamine repletion, suggesting distinct physiological bases from other muricide types.
Area of Science:
- Neuroscience
- Physiology
- Nutritional Science
Background:
- Thiamine deficiency is known to cause various neurological and physiological disturbances.
- Muricide (mouse-killing behavior) has been observed in various experimental models, but its underlying mechanisms are not fully understood.
- Previous research suggests potential links between thiamine deficiency and behavioral changes, including aggression.
Purpose of the Study:
- To investigate the effects of thiamine deficiency on blood pressure and heart rate in rats exhibiting muricide.
- To explore the relationship between cardiovascular changes and muricide behavior induced by thiamine deficiency.
- To differentiate the physiological basis of thiamine-deficiency-induced muricide from other forms of muricide.
Main Methods:
- Rats were maintained on a thiamine-deficient diet to induce deficiency and observe muricide.
- Body weight, heart rate, and blood pressure were monitored in thiamine-deficient rats, pair-fed rats, and control groups.
- Thiamine was re-administered to assess recovery of physiological parameters and muricide behavior.
Main Results:
- Thiamine-deficient rats exhibited a high incidence of muricide (72% by day 30).
- Significant decreases in body weight, heart rate (bradycardia), and blood pressure (hypotension) were observed in thiamine-deficient rats compared to controls.
- While thiamine repletion restored cardiovascular function, muricide behavior persisted, indicating a dissociation between the two.
- Blood pressure was lower in thiamine-deficient killer rats compared to non-killer rats within the deficient group.
Conclusions:
- Thiamine deficiency induces muricide and distinct cardiovascular alterations in rats.
- The persistence of muricide after thiamine repletion suggests it is not solely driven by bradycardia or hypotension.
- Thiamine-deficiency-induced muricide likely involves different physiological mechanisms compared to muricide induced by other means, such as olfactory bulb lesions.