Hypothalamic inhibition of pars intermedia Activity in the frog

Etkin, William

doi:10.1016/0016-6480(62)90087-4

Cited by 102 publications

(26 citation statements)

References 11 publications

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“…the corpus allatum and the prothoracic gland. Evidence for an inhibitory effect of the brain on the corpus allatum, an analogue of the adenohyphysis (B. Scharrer 1952), parallels that for the inhibitory neural control of the pars intermcdia of tadpoles reported by Etkin (1962).…”

Section: The Hypothalamic-adenohypophysial Systemmentioning

confidence: 67%

Neurosecretion: Beginnings And New Directions In Neuropeptide Research

Scharrer¹

1987

Annual Review of Neuroscience

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Section: The Hypothalamic-adenohypophysial Systemmentioning

confidence: 67%

Neurosecretion: Beginnings And New Directions In Neuropeptide Research

Scharrer¹

1987

Annual Review of Neuroscience

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“…Electron microscopic and electrophysiological studies showed that nerve terminals form synaptic contacts with glandular cells of the anuran PI (Iturriza, 1964;Saland, 1968;Imai, 1969;Nakai and Gorbman, 1969;Oshima and Gorbman, 1969). By the histofluorescence technique, numerous catecholaminergic varicose fibers have also been demonstrated in the anuran PI (Enemar and Falck, 1965;et al Endocrinol. Japon.…”

mentioning

confidence: 99%

“…In this response, the dispersion and concentration of melanin granules in the dermal melanophores play the most important role, and these are dependent on levels of circulating melanophore stimulating hormone (MSH) (Hadley and Bagnara, 1975). Since the transection of the hypothalamo-hypophyseal tract or the injury to the hypothalamus in both larval and adult amphibians leads to hyperactivity of the pars intermedia (PI) of the pituitary gland, the secretion of MSH is generally believed to be under inhibitory control by the hypothalamus (Etkin, 1962;Ito, 1968). Electron microscopic and electrophysiological studies showed that nerve terminals form synaptic contacts with glandular cells of the anuran PI (Iturriza, 1964;Saland, 1968;Imai, 1969;Nakai and Gorbman, 1969;Oshima and Gorbman, 1969).…”

mentioning

confidence: 99%

Dopamine and background adaptation in bullfrog tadpoles (Rana catesbeiana): A pharmacological and histofluorescence study.

1982

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Bromocryptine, a dopamine agonist, effectively inhibited the black-adaptation of prometamorphic tadpoles of the bullfrog Rana catesbeiana. The melanophore index (MI) of bromocryptine-injected tadpoles was significantly lower than that of controls. Bromocryptine was also effective in lightening the skin color of the hypophysectomized tadpoles bearing a pituitary graft. When pimozide, a dopamine receptor blocker, was given to the tadpoles adapted to a white background, the MI increased significantly and their skin color became dark. However, pimozide was not effective in darkening the skin color of the hypo-

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“…When continuity between the hypo thalamus and the PI is disrupted by lesion or transplantation to an ectopic site, the animal will remain dark, regardless of background [Etkin, 1941[Etkin, , 1962, Taleisnik et al [1967] and Bai. and Smelik [1967] have shown that median eminence (ME) lesions which sever connections between the hypo thalamus and the PI of rats produce a decrease in pituitary MSH activity.…”

Section: Smithmentioning

confidence: 99%

The Effect of Apomorphine and Ergocriptine on the Release of MSH by the Pars intermedia of Rana pipiens

Smith¹

1975

Neuroendocrinology

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In an attempt to further characterize the nature of the innervation controlling melanophore-stimulating hormone (MSH) release from the pars intermedia (PI), pellets containing either apomorphine or ergocriptine were implanted in contact with the PI of the frog, and the effect on the animal’s coloration was observed. Frogs with apomorphine implants exhibited skin pallor for several hours and those with ergocriptine implants were pallid for a few days. Hypophysectomized (HX) frogs which had been darkened with MSH regained their pallor no sooner when given an injection of apomorphine than with the vehicle. However, intact dark frogs lightened when injected with apomorphine. Frogs darkened by autotransplantation of the PI to the dorsal lymph sac were lightened by an injection of apomorphine. Frogs lightened by an ergocriptine implant on the PI and then darkened by MSH did not lighten sooner than HX frogs given an injection of MSH. Ergocriptine-containing pellets implanted in the thigh took longer to produce the same effect than those implanted in contact with the PI. Since apomorphine is known to stimulate dopamine receptors in the central nervous system, and there is some evidence that ergocriptine does also, the above evidence supports the hypothesis that dopamine receptors are present in the PI.

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Hypothalamic inhibition of pars intermedia Activity in the frog

Cited by 102 publications

References 11 publications

Neurosecretion: Beginnings And New Directions In Neuropeptide Research

Neurosecretion: Beginnings And New Directions In Neuropeptide Research

Dopamine and background adaptation in bullfrog tadpoles (Rana catesbeiana): A pharmacological and histofluorescence study.

The Effect of Apomorphine and Ergocriptine on the Release of MSH by the Pars intermedia of Rana pipiens

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