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Intra-preoptic microinjection of 17-phenyl-ω-trinor prostaglandin E2 induces hyperthermia in the rat
S233
2108 HORI,
INTRA-PREOPTIC MICROINJECTION OF 17-PHENYL-o_TRINOR PROSTAGLANDIN E2 INDUCES HYPERTHERMIA IN THE RAT. KAE OKA, TAKAKAZU OKA, MASAKO HOSOI AND TETSURO Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka 812, Japan
We have already reported that intracerebroventricular injection of prostaglandin E2 (PGE2) induces hyperthermia through EPt receptors under thermoneutral condition in the rat. In the present study, to ascertain the sites in the brain where the EPt receptor agonist act to evoke hyperthermia, we microinjected 17-phenyl-w-trinor PGE2, butaprost and M&B28767 (an EPI, EP2 and EP3 receotor agonist, respectively) (2.50 PM) into differrent sites of the rat brain and observed the changes in colonic temperature (Tco) at thermoneutral condition. Sensitive sites where 17-phenyl-w-trinor PGEZ produced a rise in Tco (> 1.2 “C) were found in the preoptic and anterior hypothalamus (POA/AH) and the nucleus of the vertical limb of the diagonal band. Intra POA/AH microinjection of 17-phenyl-cu-trinor PGE2 produced a rapidly developing, short lasting, monophasic rise in body temperature. On the contrary, intra POA/AH microinjection of butaprost or M&B28767 was almost without effect. The results provide further evidence that central PGE2 induces hyperthermia through EPt receptors in the rat.
2109
IMMUNOHISTOCHEMICAL EVIDENCE FOR INVOLVEMENT OF SEROTONERGIC NEURONS IN EFFECTS OF 2-BUTEN-4-OLIDE, AN ENDOGENOUS FEEDING SUPPRESSANT. NOBUHISA UEMURA, SETSUJI HISANO AND YOSHIHIRO FUKUI, Dept. of w, Sch. of Med., Univ. of Tokushima, Kuramoto-cho, Tokushima, 770. Japan. A short-chain sugar acid identified in plasma, 2-buten-4-olide (2-B40), acts as a potent suppressant of food intake. It has been documented that increased serotonin activity in brain causes feeding inhibition. These findings lead to a question whether brain serotonergic neurons are involved in the effects of 2-B40. To examine this, double labeling method of Fos and tryptophan hydroxylase (TpOH) immunocytochemistry was performed. Adult Wistar male rats were injected ip with 200mg 2-B40/kg and, 2hr later, were anesthetized and perfused transcardially with phosphatebuffered 4% paraformaldehyde. Free-floating sections of brains were prepared, and stained. 2-B40 induced Fos-immunoreactivity (ir) in cell nuclei in specific brain sites potentially activated by this substance. Fos-ir neurons with TpOH-ir were mainly observed in dorsal and median raphe nuclei. These results suggest that anorexic effect of 2-B40 administration may be mediated by serotonergic neurons sending strong output to the hypothalamus, and endogenous 2-B40 could participate in control of appetite in part through serotonergic system.
2110
FUNCTIONAL RECOVERY FROM THE “APHASIA” INDUCED BY UNILATERAL LESION OF SONG CONTROL NUCLEI (HVc AND RA) IN THE BENGALESE FINCH.
JUN MIKI, TOSHIYA MATSUSHIMA AND KIYOSHI AOKI, Life Sci. Inst., Sophia Univ. Tokyo 102, JaDan. In song birds, repertoire of characteristic song elements (syllables) and their rigid sequences constitute the song pattern. Where are these syllables and sequences stored in the bird brain? To answer this question, unilateral forebrain nuclei (HVc and R.A) were chemically lesioned by microinfusion of kainate, and the effects on the song patterns were examined in sexually matured male adults of the Bengalese finch (Lonchura s@&u). In all of the lesioned birds (n=lO), motif syllables (characteristic song structure) were completely lost, while saving introductory note (noncharacteristic syllable) and courtship dance during the initial days after lesioning. Some of the lesioned birds recovered from the “aphasia” of song within a few weeks. Degree of the functional recovery corresponded to degree of the remaining RA volume. (1) In two birds all of the pre-lesion yllubles reappeared until the post-lesion day 12, but their sequences remained distorted. In these birds, HVc was selectively lesioned and the ipsilataral RA remained intact. (2) In other two birds, one of the pre-lesion gdlables never reappeared and their sequences were distorted. Volume of the RA ipsilateral to the lesioning fell within a range 69-790/o of the contralateral RA. (3) In the remaining 6 bids, most of prelesion syllables never reappeared, except for the syllables which resembled introductory note. The ipsilateral R4 volume was smaller than 65% of the contralateral RA. These results suggest that HVc may encode temporal structure such as the sequence of syllables, while RA may encode acoustic structure of each syllable.
2108 HORI,
INTRA-PREOPTIC MICROINJECTION OF 17-PHENYL-o_TRINOR PROSTAGLANDIN E2 INDUCES HYPERTHERMIA IN THE RAT. KAE OKA, TAKAKAZU OKA, MASAKO HOSOI AND TETSURO Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka 812, Japan
We have already reported that intracerebroventricular injection of prostaglandin E2 (PGE2) induces hyperthermia through EPt receptors under thermoneutral condition in the rat. In the present study, to ascertain the sites in the brain where the EPt receptor agonist act to evoke hyperthermia, we microinjected 17-phenyl-w-trinor PGE2, butaprost and M&B28767 (an EPI, EP2 and EP3 receotor agonist, respectively) (2.50 PM) into differrent sites of the rat brain and observed the changes in colonic temperature (Tco) at thermoneutral condition. Sensitive sites where 17-phenyl-w-trinor PGEZ produced a rise in Tco (> 1.2 “C) were found in the preoptic and anterior hypothalamus (POA/AH) and the nucleus of the vertical limb of the diagonal band. Intra POA/AH microinjection of 17-phenyl-cu-trinor PGE2 produced a rapidly developing, short lasting, monophasic rise in body temperature. On the contrary, intra POA/AH microinjection of butaprost or M&B28767 was almost without effect. The results provide further evidence that central PGE2 induces hyperthermia through EPt receptors in the rat.
2109
IMMUNOHISTOCHEMICAL EVIDENCE FOR INVOLVEMENT OF SEROTONERGIC NEURONS IN EFFECTS OF 2-BUTEN-4-OLIDE, AN ENDOGENOUS FEEDING SUPPRESSANT. NOBUHISA UEMURA, SETSUJI HISANO AND YOSHIHIRO FUKUI, Dept. of w, Sch. of Med., Univ. of Tokushima, Kuramoto-cho, Tokushima, 770. Japan. A short-chain sugar acid identified in plasma, 2-buten-4-olide (2-B40), acts as a potent suppressant of food intake. It has been documented that increased serotonin activity in brain causes feeding inhibition. These findings lead to a question whether brain serotonergic neurons are involved in the effects of 2-B40. To examine this, double labeling method of Fos and tryptophan hydroxylase (TpOH) immunocytochemistry was performed. Adult Wistar male rats were injected ip with 200mg 2-B40/kg and, 2hr later, were anesthetized and perfused transcardially with phosphatebuffered 4% paraformaldehyde. Free-floating sections of brains were prepared, and stained. 2-B40 induced Fos-immunoreactivity (ir) in cell nuclei in specific brain sites potentially activated by this substance. Fos-ir neurons with TpOH-ir were mainly observed in dorsal and median raphe nuclei. These results suggest that anorexic effect of 2-B40 administration may be mediated by serotonergic neurons sending strong output to the hypothalamus, and endogenous 2-B40 could participate in control of appetite in part through serotonergic system.
2110
FUNCTIONAL RECOVERY FROM THE “APHASIA” INDUCED BY UNILATERAL LESION OF SONG CONTROL NUCLEI (HVc AND RA) IN THE BENGALESE FINCH.
JUN MIKI, TOSHIYA MATSUSHIMA AND KIYOSHI AOKI, Life Sci. Inst., Sophia Univ. Tokyo 102, JaDan. In song birds, repertoire of characteristic song elements (syllables) and their rigid sequences constitute the song pattern. Where are these syllables and sequences stored in the bird brain? To answer this question, unilateral forebrain nuclei (HVc and R.A) were chemically lesioned by microinfusion of kainate, and the effects on the song patterns were examined in sexually matured male adults of the Bengalese finch (Lonchura s@&u). In all of the lesioned birds (n=lO), motif syllables (characteristic song structure) were completely lost, while saving introductory note (noncharacteristic syllable) and courtship dance during the initial days after lesioning. Some of the lesioned birds recovered from the “aphasia” of song within a few weeks. Degree of the functional recovery corresponded to degree of the remaining RA volume. (1) In two birds all of the pre-lesion yllubles reappeared until the post-lesion day 12, but their sequences remained distorted. In these birds, HVc was selectively lesioned and the ipsilataral RA remained intact. (2) In other two birds, one of the pre-lesion gdlables never reappeared and their sequences were distorted. Volume of the RA ipsilateral to the lesioning fell within a range 69-790/o of the contralateral RA. (3) In the remaining 6 bids, most of prelesion syllables never reappeared, except for the syllables which resembled introductory note. The ipsilateral R4 volume was smaller than 65% of the contralateral RA. These results suggest that HVc may encode temporal structure such as the sequence of syllables, while RA may encode acoustic structure of each syllable.