Thyrotropin releasing hormone increases 5-hydroxytryptamine1 receptors in the limbic brain of the rat

Funatsu, Kunihiko; Teshima, Shigeki; Inanaga, Kazutoyo

doi:10.1016/0196-9781(85)90121-4

Cited by 15 publications

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“…The findings that TRH is co-localized with substance P and serotonin in some brain nuclei and TRH is able to increase the number of serotonin receptors [20,48] further suggest a neuromodulatorrote for TRH in the CNS. For more detailed review on the neurochemistry of TRH see the recent reviews of Prasad [43] and Sharif (48].…”

Section: Trh System In the Drainmentioning

confidence: 93%

“…Brain synaptosomes are rieb in immunoreactive TRH and immunocytochemically TRH has been shown to be present in nerve endings [42]. Moreover, TRH is released in vitro by various stimuJi to be retaken up by the rat bram shces in vitro [43].The findings that TRH is co-localized with substance P and serotonin in some brain nuclei and TRH is able to increase the number of serotonin receptors [20,48] further suggest a neuromodulatorrote for TRH in the CNS. For more detailed review on the neurochemistry of TRH see the recent reviews of Prasad [43] and Sharif (48].…”

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Cardiovascular pharmacology of thyrotropin releasing hormone

Sirén

1988

Peptides

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SIREN A.-L. Cardiovascu/ar pharmacology of thyrotropin releasing hormone. PEPTIDES 9: Suppt. l, [69][70][71][72][73] 1988.-Thyrot;opin releasing hormone (TRH) and its receptors are present in th~ car~iovascul~ nuclei ofthe brain as ~ell as in ~he intermediolateral cell column of spinal cord. Anatomical, neurophysiological, funchonal and pharmacological stud1es suggest that TRH is a neurotransmitter/neuromodulator in the centrat nervous system. Administration of TRH to experimental animals or human subjects induces pressor and tachycardic responses and increases plasma Ievels of catecholamines. These effects are likely tobe mediated by a central nervous system activation of the sympathoadrenomedullary system with no involvement of vasopressin or renin-angiotensm system. ln the conscious rat, the TR~-induced pressor response is accompanied by an increment in cardiac output and a distinct change in organ blood flow, a hmdquarter skeletal muscle vasodilation accompanied bv renal and mesenteric vasoconstriction. The rote ofTRH in hypertension has not been studied. However, the extremely potent pressor and vasoconstrictor properties of TRH makes this tripeptide a candidate for neurotransmitters/modulators involved in the development and/or maintenance ofhypertension. The role ofTRH in the therapy of shock is at present controversial. Though preliminary experimental work raised hopes and expectations for therapeutic usage of TRH in shock and trauma, the more recent studies have shown no effect or a detrimental effect for TRH in some experimental shock states. TRHBlood pressure Organ blood flow Sympathetic nerve activity THYROTROPIN releasing hormone (TRH, 1-pyroglutamyl-1-histidyl-1-prolinamide) was the first hypothalamic releasing factor to be isolated, chemically characterized and synthesized [43]. In addition to its neuroendocrine effects (TSH, prolactin, growth hormone release), this tripeptide has centrat nervous actions which are totally unrelated to its effect on the hypothalamopituitary axis (for review see [29,38]). The presence of TRH immunoreactivity and TRH receptors in brain areas related to the cardiorespiratory control, together with the extremely potent pressor and tachycardic actions of exogenously administered TRH suggest that this peptide might have a role in modulating the brain regulation of blood pressure and respiration. This review aims to summarize the sturlies on TRH in the centrat nervous system with special emphasis on the cardiovascular pharmacology of this peptide. TRH SYSTEM IN THE DRAINTRH immunoreactivity is unevenly distributed throughout the centrat nervous system (see [42,43]). Although the highest local concentrations are found in the hypothalamus (especially in the median eminence, periventricuJar arcuate, dorsomedial and ventromedial nuclei), more than 70% of the total CNS TRH is located in extrahypothalamic areas. Outside the hypothalamus high locallevels of TRH are found in the lateral nucleus of the septum in the limbic area and in the nucleus of the solitary tract (NTS) in the...

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Section: Trh System In the Drainmentioning

confidence: 93%

mentioning

confidence: 99%

Cardiovascular pharmacology of thyrotropin releasing hormone

Sirén

1988

Peptides

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Organization of serotonin 1A and 1B receptors in the nucleus of the solitary tract

Manaker¹,

Verderame²

1990

J of Comparative Neurology

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We utilized 3H-8-hydroxy-N,N-dipropyl-2-aminotetralin (3H-DPAT) and 125I-iodocyanopindolol (125I-CYP) to label serotonin (5HT) 1A and 5HT1B receptors, respectively, in sections of the rat brain after characterizing the pharmacologic specificity of these agents. We then used quantitative autoradiography to measure the concentrations of 5HT1A and 5HT1B receptors in individual subnuclei of the nucleus of the solitary tract (NTS) and adjacent structures of the dorsal vagal complex. The highest 5HT1A receptor concentrations were observed within the central and intermediate subnuclei of the NTS, with low quantities of 3H-DPAT binding sites observed in the hypoglossal nucleus and dorsal motor nucleus of the vagus. In contrast, the density of 5HT1B receptors was relatively homogeneous through all NTS subnuclei, with the highest concentrations localized within the ventrolateral subnucleus. The hypoglossal and dorsal motor nuclei had slightly higher 5HT1B receptor densities than the NTS subnuclei, whereas the area postrema had a very low density. These data suggest that 5HT1A receptors are organized in a manner consistent with the cytoarchitectural and hodological parcellation of the NTS into individual subnuclei. The high concentrations of 5HT1A receptors in the central and intermediate subnuclei suggest a role for these receptors in medullary reflex pathways subserving deglutition. The relatively high density of 5HT1B receptors in the ventrolateral subnucleus suggests that these receptors modulate respiratory neurons, whereas the diffuse organization of 5HT1B receptors in the remaining subnuclei suggests that they are associated with central 5HT afferent pathways to the NTS. Further studies will be required to understand the physiologic role of 5HT1 receptors within the NTS.

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