Repeated treatment with amitriptyline or electroconvulsive shock does not affect thyrotropin releasing hormone...

We studied the effect of repeated treatment with amitriptyline (10 mg/kg, p.o., twice daily for 14 days) or electroconvulsive shock (ECS) (once daily for 10 days) on the thyrotropin-releasing hormone (TRH) content and TRH receptors in the cerebral cortex, nucleus accumbens, striatum and septum of the rat. Repeated amitriptyline did not significantly affect the density or affinity of TRH receptors in the examined structures, but caused a marked increase in the TRH content in the striatum and nucleus accumbens. Long-term treatment with ECS reduced the density and affinity of TRH receptors in the septum only, but it increased the TRH concentration in the cerebral cortex and striatum. These results, together with the literature data, indicate that there is no simple relationship between the brain content (and release) of TRH and the functional sensitivity of TRH receptors on one hand, and the density of these receptors on the other.