Catechol-O-methyltransferase: potential relationship to idiopathic hypertension.

Catecholamine signaling pathways in the peripheral and central nervous systems (PNS, CNS, respectively) utilize catechol-O-methyltransferase (COMT) as a major regulatory enzyme responsible for deactivation of dopamine (DA), norepinephrine (NE) and epinephrine (E). Accordingly, homeostasis of COMT gene expression is hypothesized to be functionally linked to regulation of autonomic control of normotensive vascular events. Recently, we demonstrated that morphine administration in vitro resulted in decreased cellular concentrations of COMT-encoding mRNA levels, as compared to control values.

Proinflammation and preconditioning protection are part of a common nitric oxide mediated process.

In the pathophysiology of many different diseases, proinflammatory disease processes repeatedly seem to represent a basic principle. Proinflammation, as any biologic process, has the capacity of exerting negative effects, since its components are toxic and autotoxic. Since proinflammation is a common phenomenon and is, capable of executing negative 'side effects', it is understandable and plausible why it seems to be involved in many different disease states.

Dopamine, morphine, and nitric oxide: an evolutionary signaling triad.

Morphine biosynthesis in relatively simple and complex integrated animal systems has been demonstrated. Key enzymes in the biosynthetic pathway have also been identified, that is, CYP2D6 and COMT. Endogenous morphine appears to exert highly selective actions via novel mu opiate receptor subtypes, that is, mu3,-4, which are coupled to constitutive nitric oxide release, exerting general yet specific down regulatory actions in various animal tissues.

Xenobiotic perturbation of endogenous morphine signaling: paradoxical opiate hyperalgesia.

The clinical literature has extensively documented diverse, potentially debilitating, side-effects of pharmaceutical dosages of morphine and morphine congeners administered for management of acute and chronic pain. Paradoxically, morphine is capable of engendering state-dependent hyperalgesic responses that appear to be functionally linked to secondary activation of N-methyl-D-aspartate (NMDA) receptors coupled to Ca++-evoked nitric oxide (NO) production. Similar biochemical events have been associated with the development of morphine tolerance.

CYP2D6: a key enzyme in morphine synthesis in animals.

Our laboratory and others have demonstrated that animals can make morphine, meaning its biosynthetic pathway has been conserved during evolution. Among the many enzymes involved in this process, CYP2D6 is of particular importance because of its role in multiple steps of morphine precursor metabolism, as well as its distribution in a variety of tissues, such as neuronal and immune. Additionally, its genetic variations support its role in this process.

The presence of endogenous morphine signaling in animals.

Recent empirical findings have contributed valuable mechanistic information in support of a regulated de novo biosynthetic pathway for chemically authentic morphine and related morphinan alkaloids within animal cells. Importantly, we and others have established that endogenously expressed morphine represents a key regulatory molecule effecting local circuit autocrine/paracrine cellular signaling via a novel mu(3) opiate receptor coupled to constitutive nitric oxide production and release. The present report provides an integrated review of the biochemical, pharmacological, and molecular demonstration of mu(3) opiate receptors in historical linkage to the elucidation of mechanisms of endogenous morphine production by animal cells and organ systems.

Homeopathic ethanol.

Ethanol has had a long and deep association with the historical development of world culture. Ostensibly, its consumption has both short and long term positive and negative effects, based on moderate or excessive intake, respectively. The predominant thrust of empirical research, however, into the multiple biological effects of ethanol has led to its negative designation as a major addictive substance.

TENS stimulates constitutive nitric oxide release via opiate signaling in invertebrate neural tissues.

Background: There is a major societal concern relating to the addictive properties of analgesic drugs such as morphine with regard to alleviating pain. Because of this, alternative methods of pain relief are, and have been, actively pursued. An extremely promising method for treatment of low to moderate levels of chronic pain in humans is transcutaneous electrical nerve stimulation (TENS).

Endogenous morphine signaling via nitric oxide regulates the expression of CYP2D6 and COMT: autocrine/paracrine feedback inhibition.

We determined changes in mRNA expression in specific enzymes involved in the biosynthesis of morphine in human white blood cells via microarray. Leukocyte exposure to morphine down-regulated catechol-O-methyl transferase (COMT) and CYP2D6 by approximately 50% compared with control values. The treatment did not alter DOPA decarboxylase and dopamine beta-hydroxylase expression, demonstrating the specificity of morphine actions.

Nicotine, alcohol and cocaine coupling to reward processes via endogenous morphine signaling: the dopamine-morphine hypothesis.

Pleasure is described as a state or feeling of happiness and satisfaction resulting from an experience that one enjoys. We examine the neurobiological factors underlying reward processes and pleasure phenomena. With regard to possible negative effects of pleasure, we focus on addiction and motivational toxicity.

Nitric oxide's pulsatile release in lobster heart and its regulation by opiate signaling: pesticide interference.

Background: Data is emerging in the human and invertebrate literature demonstrating that mu opiate receptors and morphine are present in cardiovascular tissues in diverse animals, including human tissues, where they may be exerting a cardioregulatory role via stimulation of constitutive nitric oxide (NO) production.

Material/methods: NO release from lobster heart was evaluated without stimulation and after morphine exposure using a real-time NO-specific amperometric probe. In addition, real time NO release was evaluated after treatment with low doses of widely used pesticides (e.

Alcohol-, nicotine-, and cocaine-evoked release of morphine from human white blood cells: substances of abuse actions converge on endogenous morphine release.

Background: Normal human white blood cells (WBC) have the ability to synthesize morphine as do invertebrate ganglia. Furthermore, invertebrate neural tissues incubated with ethanol, cocaine, or nicotine results in a statistically significant enhancement of labeled morphine release. We now demonstrate that this also occurs with human WBC.

Relaxation: molecular and physiological significance.

There appears to be a molecular process for relaxation. Given this, we attempt to demonstrate this phenomenon based on established molecular and physiological processes in light of our current understanding of central and peripheral nervous system mechanisms. Central to our hypothesis is the significance of norepinephrine, nitric oxide, dopamine and morphine signaling both in the central and peripheral nervous system.

Cholinergic regulation of endogenous morphine release from lobster nerve cord.

Background: Invertebrate nervous systems are regulated by G-coupled protein receptors, chemical transporters, and ion channels responsive to established drugs of abuse including opiates, alcohol, psychostinulants, and nicotine. Thus, invertebrate nervous tissue preparations can be used as predictive model systems by which to evaluate underlying pharmacological mechanisms of addictive processes.

Material/methods: Ex vivo pharmacological trials were used to determine the comparative effects of the nicotinic agonists and antagonists on the evoked release of labeled morphine from H.

Morphine regulates gill ciliary activity via coupling to nitric oxide release in a bivalve mollusk: opiate receptor expression in gill tissues.

Background: Invertebrates express opiate receptors and synthesize opiate alkaloids such as morphine and morphine-6beta-glucuronide. Most of this work has been demonstrated in immune and neural tissues of various invertebrates. We hypothesized that morphinergic signaling may also take place in Mytilus edulis gill since they are innervated, in part, with dopamine nerves.

Alcohol-, nicotine-, and cocaine-evoked release of morphine from invertebrate ganglia: model system for screening drugs of abuse.

Background: Invertebrates express regulatory receptors, transporters, and channels responsive to established drugs of abuse, many of which mediate their effects through catecholamine pathways. We hypothesized that invertebrate neural systems may serve as models by which to evaluate the interactive pharmacological effects of these agents.

Material And Methods: Ex vivo pharmacological trials determined the effects of saturating levels of ethanol on morphine levels in pooled Mytilus edulis ganglia via HPLC coupled to electrochemical detection and/or HPLC/RIA analyses.

Human white blood cells synthesize morphine: CYP2D6 modulation.

Human plasma contains low, but physiologically significant, concentrations of morphine that can increase following trauma or exercise. We now demonstrate that normal, human white blood cells (WBC), specifically polymorphonuclear cells, contain and have the ability to synthesize morphine. We also show that WBC express CYP2D6, an enzyme capable of synthesizing morphine from tyramine, norlaudanosoline, and codeine.

Endogenous morphine: opening new doors for the treatment of pain and addiction.

Nitric oxide (NO) signalling is at the forefront of intense research interest because its many effects remain controversial and seemingly contradictory. This paper examines its role as a potential mediator of pain and tolerance. Within this context discussion covers endogenous morphine, documenting its ability to be made in animal tissues, including nervous tissue, and in diverse animal phyla.

Morphine 6beta glucuronide: fortuitous morphine metabolite or preferred peripheral regulatory opiate?

Morphine-6beta-glucuronide (M6G), a metabolite of morphine that the brain can produce, is an opiate agonist that appears to have a greater analgesic potency than morphine. M6G has a 1-octanol/water partition coefficient 187 times lower than that of morphine and M6G has a blood brain barrier permeability 57 times lower than morphine. The brain uptake rate however is only 32 times lower, suggesting that an active transport mechanism might be present.

In vivo and in vitro L-DOPA and reticuline exposure increases ganglionic morphine levels.

Background: Given the presence of morphine, its metabolites and precursors, i.e., reticuline, in mammalian and invertebrate tissues, it has become imperative to determine if exposing tissues to putative opiate alkaloid and dopamine precursors would result in increasing endogenous morphine levels.

Reticuline exposure to invertebrate ganglia increases endogenous morphine levels.

Objectives: Given the presence of morphine, its metabolites and precursors in mammalian and invertebrate tissues, it became important to determine if exposing tissues to an opiate alkaloid precursor, reticuline, would result in increasing endogenous morphine levels.

Method: Endogenous morphine levels were determined by high pressure liquid chromatography coupled to electrochemical detection and radioimmunoassay following incubation of Mytilus edulis pedal ganglia with reticuline. Nitric oxide (NO) release was determined in real-time via an amperometric probe.

Differential expression of the human mu opiate receptor from different primary vascular endothelial cells.

Background: Studies from our laboratory have identified a novel mu opiate receptor, mu3, which is expressed in several tissues, such as human vascular endothelial cells, leukocytes and invertebrate neural tissues. This novel mu receptor has been shown to be selective for opiate alkaloids, insensitive to opioid peptides, and also is coupled to constitutive nitric oxide release.

Material/methods: In this study, we compare the mu3 receptor gene expression from three different vascular endothelial primary cell lines at the molecular level using a Taqman probe for the mu opiate receptor.

Immunocytes modulate ganglionic nitric oxide release which later affects their activity level.

Pedal ganglia excised and maintained in culture for up to 2 h, release NO at low levels. The range can vary between 0 to 1.1 nM.

Morphine enhances nitric oxide release in the mammalian gastrointestinal tract via the micro(3) opiate receptor subtype: a hormonal role for endogenous morphine.

Studies from our laboratory have revealed a novel micro opiate receptor, micro(3), which is expressed in both human vascular tissues and leukocytes. The micro(3) receptor is selective for opiate alkaloids, insensitive to opioid peptides and is coupled to constitutive nitric oxide (cNO) release. We now identify the micro(3) receptor characteristics in mammalian gut tissues.

A sub-nanomolar real-time nitric oxide probe: in vivo nitric oxide release in heart.

Background: Amperometric nitric oxide probes are critical in evaluating real-time nitric oxide levels. This valuable tool enables one to measure spontaneous baseline levels of nitric oxide as well as 'puffs' of the gaseous signal molecule that may last for only seconds to minutes. However, in the past, many probes suffered from a lack of sensitivity, durability and reliability, causing investigators to design numerous controls to support their data.