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Relationships between the effects of peripherally administered salmon calcitonin on calcaemia and brain biogenic
R Gaggi1, R De Iasio, A M Gianni
1Institute of Pharmacology, University of Bologna, Italy.
Abstract:
The effects of s.c. administered salmon calcitonin on the biogenic amine neurotransmitters and metabolites were studied in discrete brain sections in order to evaluate the relationships between these central effects and the fall of serum calcium and to investigate the mechanisms of calcitonin-induced behavioral changes. The biogenic amines and metabolites were simultaneously determined by high-performance liquid chromatography with electrochemical detection in tissue samples obtained from rats treated with 10-80 MRC U/kg of the peptide. Some rats were pretreated with calcium lactate to inhibit the calcitonin-induced hypocalcaemia. Most of the effects, consisting of signs of serotonergic system activation, have been observed in the hypothalamus, accounting for some behavioral effects of the peripherally administered salmon calcitonin. It was speculated that the activation of the brain serotonergic system could result from two indirect and separate mechanisms: the first, which would involve enhanced serotonin synthesis, seemed to be facilitated by calcium availability. A second possible mechanism, which would involve enhanced serotonin release from the neurons, seemed to be mediated by the fall of calcium levels in the blood.
Insights
Salmon calcitonin activates the brain
Area of Science:
- Neuroendocrinology
- Neuropharmacology
Background:
- Calcitonin's central nervous system effects are not fully understood.
- Investigating calcitonin's impact on neurotransmitters is crucial for understanding its behavioral effects.
Purpose of the Study:
- To investigate the effects of salmon calcitonin on brain biogenic amines.
- To correlate central neurotransmitter changes with hypocalcemia and behavioral alterations.
Main Methods:
- Salmon calcitonin administered subcutaneously to rats at varying doses (10-80 MRC U/kg).
- Biogenic amines and metabolites measured using high-performance liquid chromatography with electrochemical detection.
- Hypocalcemia inhibited in some groups using calcium lactate pretreatment.
Main Results:
- Salmon calcitonin administration led to significant changes in brain biogenic amines and metabolites.
- Hypothalamic serotonergic system activation was a prominent finding.
- These central effects correlated with peripheral hypocalcemia and behavioral changes.
Conclusions:
- Peripheral salmon calcitonin influences central neurotransmitter systems, particularly serotonin.
- Both calcium availability and hypocalcemia may play roles in mediating calcitonin's effects on serotonin synthesis and release.