Microinjection of leptin into the ventromedial hypothalamus increases glucose uptake in peripheral tissues in rats

s252

HEAT PRODUCTION

545

VENTROMEDIAL

AKIKO KOBAYASHI’

IN THE BROWN ADIPOSE

HYPOTHALAMIC

, TOSHIMASA

OSAKA’,

TISSUE BY CGRP INJECTION

INTO THE

NUCLEUS

SHUJI IINOUE’ . SHUICHI KIMURA’

‘Graduate School of Showa Women’s Univ., Course of Science for Living System, l-7 Taishido, Setagaya 2Nationa1 Institute of Health and Nutrition, We previously

1-23-1 Toyama, Shinjuku 162-8636, Japan

reported that a microinjection

of calcitonin

nucleus (VMH) increased oxygen consumption, present study, we investigated increased temperature

the peripheral

of interscapular

(5 mg/kg, i.p.), a P-adrenergic

the CGRP-induced

gene-related

peptide (CGRP) into the ventromedial

heart rate, and colonic temperature

mechanism

of the CGRP-induced

inhibited the CGRP-induced

These results suggest that CGRP stimulates

enhancement

of the sympathetic

l3 receptor-mediated

In the

Pretreatment

with propranolol heart rate,

nerves that innervate the IBAT attenuated

In rats with adrenal demedullation,

production.

rats.

The CGRP injection

increases in oxygen consumption,

A surgical cutting of the bilateral sympathetic

increase in oxygen consumption.

hypothalamic

in urethane-anesthetized

heat production.

brown adipose tissue (IBAT) larger than that of colon.

receptor antagonist,

and colon and IBAT temperature.

154-0024. Japan,

CGRP normally activated heat

thermogenesis

in the BAT through the

nervous activity.

LIGHT AND ELECTRON MICROSCOPICAL STUDIES OF PACAP (PITUITARY ADENYLATE CYCLASE ACTIVATING PEPTIDE) IMMUNOREACTIVE NEURONS IN THE ENTERIC NERVOUS SYSTEM OF RAT SMALL AND LARGE INTESTINE.

546

MASATO NAGAHAMA’,

MASAKO TSUZUKll,

TOHRU MOCHIZUK12, KAZUAKI IGUCH12 and ATSUKAZU

KUWAHARA2 1 Institute for Developmental Research, 713-8 Kamiya-cho, Kasugai, Aichi 480-0392, Japan. 2University of Shizuoka, Shizuoka 422-8526, Japan. Pituitary adenylate cyclase activating peptide (PACAP) is VIP-like hypothalamic peptide that is widely distributed in neurons in CNS and enteric nervous system. PACAP immunoreactive (IR) neurons in the myenteric and submucosal plexus of the rat small and large intestine were examined by immunostaining with purified polyclonal antiserum against PACAP (l-15) using both light and electron microscopy. Many PACAP-IR neuronal cell bodies and fibers were found in the myenteric and submucosal plexus. Many of the PACAP-IR fibers originated from the cell bodies of the myenteric and submucosal ganglia. The ganglia were also innervated by PACAP-IR fibers. PACAP-IR fibers penetrated both the circular and longitudinal muscle layers, confirming the previous observations indicating that PACAP neurons act as motor neurons. Ultrastructural study demonstrated that PACAP-IR nerve terminals formed synaptic contacts with PACAP-IR nerve cell bodies or dendritic processes. This observation suggests that PACAP-IR neurons innervate other PACAP-IR neurons, and that PACAP neurons work as interneurons in the enteric nervous system. PACAP-IR nerve cells received not only PACAP positive nerve terminal input also PACAP negative nerve terminal input. It also suggests that PACAP neurons are regulated not only by PACAP-IR enteric neurons, but also by neurons originating elsewhere. Our observations support the view that PACAP-IR neurons are involved in the control of gut motility.

547 YASUHIKO

MICROINJECTION

OF LEPTIN

GLUCOSE

IN PERIPHERAL

UPTAKE

MINOKOSHI,

MOHAMMAD

Dept. of Medical Biochemistry,

Effects of microinjection

INTO THE VENTROMEDIAL TISSUES

SHAHIDUL

INCREASES

IN RATS

HAQUE AND TAKASHI

Ehime Univ. School of Medicine,

of leptin into the ventromedial

HYPOTHALAMUS

Shigenobu,

hypothalamus

SHIMAZU

Ehime 791-0295

(VMH) and lateral hypothalamus

(LH) on glucose

uptake in peripheral tissues were studied in unanesthetized rats. The rate of glucose uptake was assessed in vivo by the 2[3H]deoxyglucose heart, skeletal glucose

method.

muscles

Injection

and spleen,

of leptin into the VMH increased but not in white adipose

uptake was greater in slow-twitch

glucose uptake in BAT to intra-hypothalamic tissue.

oxidative

tissue or skin.

Among skeletal

fibers than that in fast-twitch

leptin was completely

suppressed

glycolitic

tissues

preferentially

muscles, fibers.

by local sympathetic

Leptin injected into the LH, on the other hand, had little effects in any peripheral

that leptin enhances glucose uptake in some peripheral system.

glucose uptake in brown adipose

tissues.

tissue (BAT), the increase

in

The response

of

denervation

These findings

through the VMH-sympathetic

of the suggest nervous