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Biomedical subjects

P Holzer

Publications and source records attributed to P Holzer.

At least 199 records · Page 11Linked to original sources
PubMed1981

Release of histamine by substance P.

1. The basic peptide substance P causes histamine release from peritoneal mast cells of the rat in vitro whereas the closely related neutral peptides eledoisin and physalaemin do not. 2. Infusion of substance P (7.4 nmol min-1), but not of eledoisin (8.4 nmol min-1) or physalaemin (7.9 nmol min-1), into the rat hindquarter preparation caused a more than 4-fold increase of the histamine content in the venous outflow. The outflow of 5-HT remained unchanged under infusion of all three peptides. 3. No histamine depletion in the skin of the rat hind paw was observed following antidromic stimulation of the saphenous nerve or cutaneous application of mustard oil. Infusion of substance P (7.4 nmol min-1) caused a 47% depletion of histamine in the paw skin although only a small proportion of the infused substance P seemed to enter the tissue from the blood vessels. 4. The results further substantiate the view that substance P upon release from peripheral nerve endings induces release of histamine from cutaneous mast cells, a mechanism which contributes to neurogenic vasodilatation and plasma extravasation.

Animals↗
PubMed1980

Distribution of substance P in the rat gastrointestinal tract--lack of effect of capsaicin pretreatment.

A new method for extraction of immunoreactive substance P (I-SP) from rat intestine including pulverization of tissue frozen in liquid nitrogen and extraction with acid acetone is described. Using this method, amounts of I-SP in the rat intestine were found to be higher than previously reported. The highest concentrations of I-SP were found in the small intestine. Capsaicin pretreatment of newborn or adult rats had no effect on intestinal I-SP concentrations indicating that intrinsic SP neurones are capsaicin-insensitive.

Animals↗
PubMed1980

Neurally mediated contraction of ileal longitudinal muscle by substance P.

The time course of the spasmogenic effect of substance P (SP) on the longitudinal muscle (LM) of the guinea-pig ileum was investigated. Maximum effective concentrations of SP (greater than or equal to 10 ng/ml) produced a fast initial response which subsequently declined to about 50% of the initial contraction. This remaining half-maximum contraction was increased by physostigmine and decreased by tropicamide, morphine, and tetrodotoxin; hexamethonium had no effect. The results indicate that SP, apart from its direct action on the LM, also activates cholinergic neurones innervating the LM.

Animals↗
PubMed1980

Decrease of substance P in primary afferent neurones and impairment of neurogenic plasma extravasation by capsaicin.

1 Rats were pretreated with capsaicin (50 mg/kg, s.c.) on the 2nd, 10th, or 20th day of life. Three months later immunoreactive substance P (I-SP) was determined in skin, sensory nerves and the central nervous system. Neurogenic plasma extravasation was also examined.2 Pretreatment at the age of 2 or 10 days resulted in a decrease (26 to 69%) of I-SP in skin, saphenous and vagus nerve, dorsal roots, dorsal half of the spinal cord, and medulla oblongata. The I-SP content of the ventral half of the spinal cord, of midbrain, hypothalamus, striatum, cortex, and cerebellum remained unchanged. Neurogenic plasma extravasation was inhibited by more than 80%.3 In contrast to this irreversible effect of capsaicin on newborn rats, pretreatment of 20 day old rats led to reversible depletion of I-SP and to reversible impairment of neurogenic plasma extravasation.4 Capsaicin pretreatment of adult rats caused a marked depletion of I-SP in the skin of the hind paw and an impairment of neurogenic plasma extravasation. A similar decrease of I-SP was seen after chronic denervation of the skin.5 Intra-arterial infusion of substance P (threshold dose 5 x 10(-13) mol/min) or physalaemin induced dose-dependent plasma extravasation. Somatostatin, vasoactive intestinal polypeptide, caerulein and the enkephalin-analogue FK 33-824 were ineffective in doses 100 fold higher.6 The results indicate that the action of capsaicin on substance P neurones is restricted to primary sensory neurones. Since in every case a decreased substance P content of the skin was associated with impaired neurogenic plasma extravasation, it is suggested that release of substance P is involved in neurogenic plasma extravasation.

Animals↗
PubMed1979

[Early operation of patients with life threatening hemorrhage from an intracerebral arteriovenous angioma (author's transl)].

In the last twenty years 113 arteriovenous angiomas were treated at the University Clinic for Neurosurgery in Graz. Contrary to earlier practice tending towards conservative measurements in acute hemorrhage improved technic and close cooperation between the radiologist, the anaesthesist and the neurosurgeon have resulted in a diminished operative risk and made early operative intervention possible. Operation even in patients with an acute life threatening hemorrhage improve the prognosis markedly. This is demonstrated by a case report.

Angiography↗
PubMed1979

Nociceptive threshold after neonatal capsaicin treatment.

The nociceptive threshold as determined by the reaction time in the hot-plate and tail-flick tests was measured 3 to 4 months after pretreatment of young rats with capsaicin (50 mg kg-1 s.c.). The reaction time in the tail-flick test was prolonged in rats pretreated with capsaicin on the 2nd day of life. Capsaicin pretreatment up to the 10th day of life also resulted in a prolonged reaction time in the hot-plate test whereas capsaicin pretreatment after the 10th day of life was without effect. The elevation of the nociceptive threshold after neonatal capsaicin pretreatment most likely follows from degeneration of afferent nerve fibres activated by noxious stimuli.

Animals↗
PubMed1979

Transient apnoea after systemic injection of GABA in the rat.

1. I. v. or i.a. injection of GABA produced a transient apnoea in rats under pentobarbital anaesthesia. The dose-response relationship and specifity of this effect were investigated. 2. Injection of GABA into the femoral vein led to an apnoea of dose-dependent duration, the dose-response curve showed an ED50 of about 5 mumoles GABA kg-1 and a maximum duration of about 8 s. 3. The depressant action of systemic GABA on respiration seems to be specific as only close structural analogues of GABA such as trans-4-aminocrotonic acid, beta-hydroxy-GABA, delta aminovaleric acid, beta-alanine, and taurine were able to mimic the action of GABA. 4. Injection of these structural analogues of GABA 15 s rior to an injection of GABA inhibited the respiratory depressant effect of GABA dose-dependently. Picrotoxin also antagonized the apnoic action of GABA. 5. The results indicate that the apnoea induced by systemic injection of GABA is mediated by an action on GABA receptors.

Animals↗
PubMed1979

Longitudinal contraction of isolated guinea-pig ileum induced by rapid cooling.

1. Rapid change of bath temperature from 37 degrees C to 27 degrees C and vice versa caused longitudinal contraction of the isolated guinea-pig ileum. 2. Tetrodotoxin, tropicamide, noradrenaline, isoprenaline, morphine, and the met-enkephalin analogue FK 33-824 depressed the responses or accelerated the fade of the contraction induced by rapid cooling when added after the response had reached its maximum. 3. Hexamethonium had no influence on the responses. 4. Physostigmine potentiated all responses and reversed the fade of contraction induced by rapid cooling when added after this contraction had reached its maximum. 5. The effects of rapid cooling or warming were not altered in preparations made tachyphylactic to substance P; the response to rapid warming, but not cooling, was partially inhibited under tachyphylaxis to 5-hydroxytryptamine. 6. Antazoline, phentolamine, naloxone, and indomethacin did not block the responses. 7. Capsaicin firt potentiated and subsequently depressed the responses to both rapid cooling and warming. 8. The results indicate that rapid change of bath temperature induces longitudinal contraction by excitation of postganglionic cholinergic fibres.

Animals↗
PubMed1979

Indirect evidence for presynaptic location of opiate receptors on chemosensitive primary sensory neurones.

1. Rats were pretreated with 50 mg/kg s.c. capsaicin or solvent on the second day of life; 5 months later 3H-diprenorphine binding to homogenates of the whole spinal cord or of the upper dorsal horn of the spinal cord was investigated. 2. Capsaicin pretreatment resulted in a 17% decrease of opiate binding sites in the whole spinal cord and a 37% decrease in the upper dorsal horn with no change in their affinity. 3. Since neonatal capsaicin pretreatment causes degeneration of chemosensitive primary sensory neurones it is concluded that some opiate receptors are located presynaptically on the central terminals of these neurones.

Animals↗