Twenty adult male rats, weighing 200～300 g were divided into 3 groups: (1) Six. animals were stimulated through two electrodes fixed on the tail to produce somatic pain.(2) Six animals were stimulated by increasing pressure in the stomach through an air balloon to cause visceral pain. And 8 animals served as control.All the animals were sacrificed and their neurohypophysis were fixed in 4％ glutaraldehyde and 1％ OsO_4 successively. Their section were cut with an LKB microtome and observed under H 500 electron microscope.The experimental results summarized as follows:1. The bodies of pituicytes under the pain stimulation were hypertrophied. The rough endoplasmic reticulum, polyribosomes and mitochondria were increased. The Golgi complex was well developed. There were numerous elliptical vesicles appearing in the cytoplasm of pituicytes.2. The number of large lipid masses was increased while the processes of pituicytes engulfed the degenerative neurosecretory terminal into them and the pituicyte digted it finally.3. Neurosecretory granules were decreased but the synaptic small vesicles were increased in the dilated parts of neurosecretory fibers after the pain stimulation.4. The continuous network of perivascular space and interstitial space between the dilated parts of neurosecretory fibers were widened.

Pain just tolerable was caused intermittently by electric stimulation on rat's tail or by distented baloon in stomach for 30 min. The changes of intermediate lobe are summarized as follows: (1) The cell body, nucleus or nucleolus was hypertrophied. The number of rough endoplasmic reticulum, particularly of its vesicular cisternae was increased. Golgi complex enlarged. The ribosome multiplied. All of these change indicated that the activity of cells was increased and the rate of synthesis enhanced. (2) Both the secretory granules shifted to the periphery of cell body and some of them showed pale density. These changes were interpreted as increase of seretory activity. (3) The mitochondria became enlarged and the crsitae in them were changed into tubular form. This suggested an acceleration of cell metabolism, which might provide a large amount of energy. (4) There was no degenerative change. (5) The cytological changes caused by visceral pain were simillar with, but more striking than, those caused by somatic pain. (6) The secretions were increased, among which ?-endorphin and ACTH etc were known to be closely related to analgesia.

Our experiments were designed to observe the cytological changes of the anterior lobes in rats pituitary at electron microscopic level after electric pain-stimulation. obvious changes were founded in the ACTH, GH and PRL cells and slight changes in the FSH and TSH cells. However, the LH cells remained to resemble the normal cells. In the experiment group of the somatic painful stimulation the results were as follows: The ACTH cells were irregularly shaped, with extended thin and long plasmatic processes which interdigitated with GH cells. The processes filled with secretory granules. Some of the Secretory granules aligning along the plasmatic membrane showed pale density. The flat cisternae of rough endoplasmic reticulum (RER) appeared to be slightly dilated. The sizes of the bodies of GH and PRL cells increased. In the GH cells there were numera media cisternae in RER, their Golgi complex was well developed, and the secretory granules were distributed to the periphery of the cell bodies. All these phenomenous showed the secretory activity of these cells was enhanced. The PRL cells contained well developed Golgi complex and abundant RER. In the experiment group of the visceral painful stimulation the results were as follows: There were more striking changes of parenchymal cells of anterior lobes in rats pituitary than those of the experimental group of the somatic painful stimulation. The cell bodies of ACTH, GH and PRL cells showed hypertrophy, the nucleus enlarged and nucleolus were relatively prominent. The dense granules decreased in number and the pale or empty visicles almost situated near the plasmic membrane in ACTH cells. In the GH cells large vacuoles were distributed throughout the cytoplasma. The number and density of the secretory granules decreased. In PRL cells the Golgi complex were extended, the dictyosomes increased, in addition, RER, polyribosomes and mitochandria were more aboundant than that in these normal cells. These cytological changes suggested secretory and synthetic activity of these cells were enhanced. At last, pain in relation to several hormones such as ?-endorphin, ?-LPH, ACTH and ?-MSH etc. were discussed by the author.

The purpose of this research work is to study the influence of experimentally produced pain on the uhrastructural changes of the nerve endings of the neurosecretory fibers from hypothalamus to neurohypophysis.Twenty adult male rats, weighing 200～300 g were divided into 3 groups: (1) Six animals were stimulated through two electrodes fixed on the tail to produce somatic pain. (2) Six animals were stimulated by increasing pressure in the stomach through an air balloon to cause visceral pain. And 8 animals served as control.All the animals were sacrificed and their neurohypophysis were fixed in 40％ glutaraldehyde and 1％ OsO_4 successively. Sections were cut with an LKB microtome and observed under H500 electron microscope.The following conclusions were drawn from the observed results:1. The neurosecretory granules in the fibers from hypothalamus to neurohypophysis grew up to maturity by increasing in size gradually as they passing down from hypothalamus to neurohypophysis.2. Basing on the morphological exhibition of the neurosecretory granules, we get the impression that the neurosecretion might be released either by molecular dispersion or by exocytosis.3. There were a great number of discrete smooth vesicles grouped in cluster in the dilated parts of neurosecretory fibers. These vesicles had been called as "synaptic" or "synaptoid" vesicles. They might be really synaptic vesicles and containing acetylcholine. Other vesicles with irregular profile and varying in size, collapsing vesicles and vacuoles might be the residues of the neurosecretory granules after discharging their content.4. Many synaptic vesicles were concentrated at the axolemma of the dilated parts of neurosecretory fibers and the membranes were thickened and leaving a synaptic cleft.5. In the exprimental groups after pain stimulation the neurosecretory granules decreased in number and the synaptoid vesicles increased in number and the neurosecretory granules showed a wide pale halo. The number of irregular vesicles and ghost of granules were increased. This phenomenon might show that the excretion of neurosecretory material and neurotransmitters was enhanced.6. Neurohemal zones were the barrier for the neurosecretory material entering into blood. Acetylcholine, endogenous opiatelike substances and gamma-aminobutyric acid (GABA) might play a control role for neurosecretion at this site.7. This experimental results supported the action mechanism of endogenous opaitelike substance and morphine could produce an important role directly in neurohypophysis.

Ten adult male rats of 250～300 g were used. These animals were divided into the control and experimental groups of 6 and 4 rats respectively. The changes of the ultrastructure of adrenocortical cells under acupuncture analgesia were observed with electron microscopy.1. The volumes of cells, nuclei and nucleoli in zona fasciculata were increased. The mitochondria was hypertrophic; its cristae transformed from the tubules into the vesicles in the external zone fasciculate. The giant mitochondria which contained paracrystallin and lipid osmiophilic substance was observed.2. The surface volume of SER membrane was increased. The smooth membrane vesicles and tubules with filaments and granules were dilated. The SER membrane vesicles were arranged around the mitochondria or lipid droplets.3. The lipid droplets with low density were dilated and accumulated in the middle part of cytoplasm. These findings might be correlated with enhancement of synthesis and utilization of cholesterol ester.4. The free ribosomes and polysomes which scattered in cytoplasm were increased. The Golgi apparatus were well developed. The lysosomes of variable sizes and densities (primary or secondary lysosomes) were abundent.5. The number and diameter of the microvilli were increased. The spaces between the adjacent cells of zona fasciculata were dilated and the intermedian junctions and gap junctions had disappeared. The subsinus space was dilated and contained numerous longer microvilli. The changes discribed above suggested that the acupuncture analgesia may enhance activity of the adrenocortical cells, both synthesis and discharge of corticoid hormone.

Effective analgesia was induced by electro-acupuncture stimulating the "Zusanli"(足三里) point in the rats. The animal were sacrificed and as soon as possible and the median eminence were taken out from the brian. The specimens were fixed in glutaraldehyde, then were prepared for electron microscope observation.Twelve male adult rats were divided into control and experimental groups. There were many terminal enlargements in the fibrous zone of rat's median eminence. Different types of vesicles were found in the terminal buttons, they were round clear and flattened clear vesicles, and large or small vesicles with a dense core. There were also mixed forms, and irregular vesicles in the same button. Synapses may be axo-dendrits, axo-axon or axe-somatic synaptic types.The neurous in the fibrious zone could be classified into "light" and "dark" cells. The light cells might be the neurosecretory neurons. The neuroglia cells were oligodendrocytes and astrocytes.In acupuncture analgesia experimental group the terminal enlargment contained less number of round clear vesicles than that of the control group, and sometime they were empty. This may indicate the discharge of acetylcholine, to increase the secretion of the neurosecretory substance and enkephalin. But the flattened clear vesicles had no change in the terminal button. The neurons and neroglia also exhibited some morphological changes which may indicate the cells were in active functional state.