Effects of the mixed mu/kappa opioid nalbuphine on cocaine-induced changes in subjective and cardiovascular responses in men

Exploring nalbuphine loaded chitosan nanoparticles for effective pain management through intranasal administration: a comparative study

BACKGROUND

Intranasal drug delivery shows potential for brain access via olfactory and trigeminal routes.

PURPOSE

This work aimed to ensure brain availability of nalbuphine via the nasal route.

METHOD

Chitosan based nanoparticles loaded with nalbuphine were successfully prepared using ionic gelation method and characterised.

RESULT

SEM results revealed that the nanoparticles were spherical in shape, with an average size of 192.4 ± 11.6 nm. Zeta potential and entrapment efficiency was found 32.8 mV and 88.43 ± 7.75%, respectively. The X-ray diffractometry and DSC results unravel a profound understanding on the physical and thermal characteristics. The in-vitro release of nalbuphine from the nanoparticles was biphasic, with an initial burst release followed by a slow-release profile. In-vitro cell study on HEK-293 cells and microscopic images of brain tissue confirmed the safety profile of formulation. In-vivo efficacy studies on animal confirmed the effectiveness of developed intranasal formulation as compared to the standard therapy. The in-vivo pharmacokinetic studies showed that the prepared nanoparticles were able to efficiently deliver nalbuphine to the brain in comparison to the other body organs. Gamma scintigraphy images showed retention of the drug in the brain. Furthermore, the efficacy studies confirmed that the nanoparticles were found significantly more effective than the marketed formulation in pain management.

Nalbuphine's Hemodynamic Impact in Ear, Nose, and Throat (ENT) Surgeries: A Comprehensive Review

Nalbuphine, a semi-synthetic opioid, has gained attention for its analgesic properties, but its specific impact on hemodynamics in ear, nose, and throat (ENT) surgeries remains a subject of exploration. This comprehensive review aims to systematically analyze existing literature to understand the nuanced hemodynamic effects of nalbuphine during ENT procedures. Nalbuphine demonstrates promise as an analgesic agent in ENT surgeries with generally stable hemodynamic profiles. However, the variability in study designs and outcomes necessitates a cautious interpretation. The review underscores the need for standardized protocols and further research to elucidate patient-specific considerations, ensuring optimal utilization of nalbuphine in enhancing overall perioperative care for ENT patients.

A systematic review on the kappa opioid receptor and its ligands: New directions for the treatment of pain, anxiety, depression, and drug abuse

Kappa opioid receptor (KOR) is a member of the opioid receptor system, the G protein-coupled receptors that are expressed throughout the peripheral and central nervous systems and play crucial roles in the modulation of antinociception and a variety of behavioral states like anxiety, depression, and drug abuse. KOR agonists are known to produce potent analgesic effects and have been used clinically for the treatment of pain, while KOR antagonists have shown efficacy in the treatment of anxiety and depression. This review summarizes the history, design strategy, discovery, and development of KOR ligands. KOR agonists are classified as non-biased, G protein-biased, and β-arrestin recruitment-biased, according to their degrees of bias. The mechanisms and associated effects of the G protein signaling pathway and β-arrestin recruitment signaling pathway are also discussed. Meanwhile, KOR antagonists are classified as long-acting and short-acting, based on their half-lives. In addition, we have special sections for mixed KOR agonists and selective peripheral KOR agonists. The mechanisms of action and pharmacokinetic, pharmacodynamic, and behavioral studies for each of these categories are also discussed in this review.

Differential Effects of a Novel Opioid Ligand UTA1003 on Antinociceptive Tolerance and Motor Behaviour

Analgesic tolerance is a major problem in the clinic for the maintenance of opioid-induced long-term pain relief. Opioids with mixed activity on multiple opioid receptors promise reduced antinociceptive tolerance in preclinical studies, but these compounds typically show poor bioavailability upon oral, subcutaneous, intraperitoneal, or intravenous administration. We designed UTA1003 as a novel opioid that acts as a mu (MOP) and kappa (KOP) opioid receptor agonist and a partial agonist for delta (DOP) opioid receptor. In the present study, its antinociceptive effects, as well as its effects on antinociceptive tolerance and motor behaviour, were investigated in male rats. Acute antinociception was measured before (basal) and at different time points after subcutaneous injection of UTA1003 or morphine using the tail flick and hot plate assays. Various motor behavioural activities, including horizontal locomotion, rearing, and turning, were automatically measured in an open-field arena. The antinociceptive and behavioural effects of repeated administration of UTA1003 and morphine were determined over eight days. UTA1003 induced mild antinociceptive effects after acute administration but induced no tolerance after repeated treatment. Importantly, UTA1003 co-treatment with morphine prevented antinociceptive tolerance compared to morphine alone. UTA1003 showed less motor suppression than morphine in both acute and sub-chronic treatment regimens, while it did not affect morphine-induced motor suppression or hyper-excitation. Based on these activities, we speculate that UTA1003 crosses the blood-brain barrier after subcutaneous administration and, therefore, could be developed as a lead molecule to avoid opioid-induced antinociceptive tolerance and motor suppression. Further structural modifications to improve its antinociceptive effects, toxicity profile, and ADME parameters are nevertheless required.

Pain management of nalbuphine and sufentanil in patients admitted intensive care unit of different ages

Background

Pain relief for patients in the intensive care unit (ICU) can improve treatment outcomes and reduce the burden on doctors and nurses. This study aims to report the clinical analgesic and sedative effects of nalbuphine and sufentanil on ICU patients.

Methods

This study retrospectively analyzed the medical records of 87 critically ill patients who received nalbuphine or sufentanil infusion in the ICU, including demographic data, diagnosis, Acute Physiology and Chronic Health Evaluation (APACHE) II, Critical Care Pain Observation Tool (CPOT), Richmond Agitation-Sedation Scale (RASS), systolic and diastolic blood pressure, heart rate and blood oxygen saturation (SpO2). The primary outcomes of this study were CPOT and RASS scores. The secondary outcomes were hemodynamic changes, including systolic blood pressure, diastolic blood pressure, heart rate, and SpO2. The adverse events recorded during pain management, such as hypoxemia, respiration depression and bradycardia, were also collected and analyzed.

Results

None of the patients in both groups experienced episode of hypoxemia, respiration depression and bradycardia. However, age-stratified analyses showed that nalbuphine has a better analgesic effect than sufentanil for patients aged ≤ 60 (P < 0.05). In contrast, sufentanil showed a better analgesic effect than nalbuphine for patients aged > 60 ( P < 0.05). Furthermore, nalbuphine has a significantly better sedative effect than sufentanil for patients aged ≤ 60 (P < 0.05).

Conclusion

ICU patients of different age groups may be suitable for different analgesics. For patients under the age of 60, nalbuphine has better analgesia and sedation than sufentanil, and does not cause respiratory depression and drastic hemodynamic changes.

Strategies for Developing κ Opioid Receptor Agonists for the Treatment of Pain with Fewer Side Effects

There is significant need to find effective, nonaddictive pain medications. κ Opioid receptor (KOPr) agonists have been studied for decades but have recently received increased attention because of their analgesic effects and lack of abuse potential. However, a range of side effects have limited the clinical development of these drugs. There are several strategies currently used to develop safer and more effective KOPr agonists. These strategies include identifying G-protein-biased agonists, developing peripherally restricted KOPr agonists without centrally mediated side effects, and developing mixed opioid agonists, which target multiple receptors at specific ratios to balance side-effect profiles and reduce tolerance. Here, we review the latest developments in research related to KOPr agonists for the treatment of pain. SIGNIFICANCE STATEMENT: This review discusses strategies for developing safer κ opioid receptor (KOPr) agonists with therapeutic potential for the treatment of pain. Although one strategy is to modify selective KOPr agonists to create peripherally restricted or G-protein-biased structures, another approach is to combine KOPr agonists with μ, δ, or nociceptin opioid receptor activation to obtain mixed opioid receptor agonists, therefore negating the adverse effects and retaining the therapeutic effect.

Multifunctional Opioid Ligands

The opioid receptor system plays a major role in the regulation of mood, reward, and pain. The opioid receptors therefore make attractive targets for the treatment of many different conditions, including pain, depression, and addiction. However, stimulation or blockade of any one opioid receptor type often leads to on-target adverse effects that limit the clinical utility of a selective opioid agonist or antagonist. Literature precedent suggests that the opioid receptors do not act in isolation and that interactions among the opioid receptors and between the opioid receptors and other proteins may produce clinically useful targets. Multifunctional ligands have the potential to elicit desired outcomes with reduced adverse effects by allowing for the activation of specific receptor conformations and/or signaling pathways promoted as a result of receptor oligomerization or crosstalk. In this chapter, we describe several classes of multifunctional ligands that interact with at least one opioid receptor. These ligands have been designed for biochemical exploration and the treatment of a wide variety of conditions, including multiple kinds of pain, depression, anxiety, addiction, and gastrointestinal disorders. The structures, pharmacological utility, and therapeutic drawbacks of these classes of ligands are discussed.

Placement of Hydroxy Moiety on Pendant of Peptidomimetic Scaffold Modulates Mu and Kappa Opioid Receptor Efficacy

In an effort to expand the structure–activity relationship (SAR) studies of a series of mixed-efficacy opioid ligands, peptidomimetics that incorporate methoxy and hydroxy groups around a benzyl or 2-methylindanyl pendant on a tetrahydroquinoline (THQ) core of the peptidomimetics were evaluated. Compounds containing a methoxy or hydroxy moiety in the o- or m-positions increased binding affinity to the kappa opioid receptor (KOR), whereas compounds containing methoxy or hydroxy groups in the p-position decreased KOR affinity and reduced or eliminated efficacy at the mu opioid receptor (MOR). The results from a substituted 2-methylindanyl series aligned with the findings from the substituted benzyl series. Our studies culminated in the development of 8c, a mixed-efficacy MOR agonist/KOR agonist with subnanomolar binding affinity for both MOR and KOR.

A translational pharmacology approach to understanding the predictive value of abuse potential assessments

Within the drug development industry the assessment of abuse potential for novel molecules involves the generation and review of data from multiple sources, ranging from in-vitro binding and functional assays through to in-vivo nonclinical models in mammals, as well as collection of information from studies in humans. This breadth of data aligns with current expectations from regulatory agencies in both the USA and Europe. To date, there have been a limited number of reviews on the predictive value of individual models within this sequence, but there has been no systematic review on how each of these models contributes to our overall understanding of abuse potential risk. To address this, we analyzed data from 100 small molecules to compare the predictive validity for drug scheduling status of a number of models that typically contribute to the abuse potential assessment package. These models range from the assessment of in-vitro binding and functional profiles at receptors or transporters typically associated with abuse through in-vivo models including locomotor activity, drug discrimination, and self-administration in rodents. Data from subjective report assessments in humans following acute dosing of compounds were also included. The predictive value of each model was then evaluated relative to the scheduling status of each drug in the USA. In recognition of the fact that drug scheduling can be influenced by factors other than the pharmacology of the drug, we also evaluated the predictive value of each assay for the outcome of the human subjective effects assessment. This approach provides an objective and statistical assessment of the predictive value of many of the models typically applied within the pharmaceutical industry to evaluate abuse potential risk. In addition, the impact of combining information from multiple models was examined. This analysis adds to our understanding of the predictive value of each model, allows us to critically evaluate the benefits and limitations of each model, and provides a method for identifying opportunities for improving our assessment and prediction of abuse liability risk in the future.

The mu/kappa agonist nalbuphine attenuates sensitization to the behavioral effects of cocaine

Sensitization refers to an increase in sensitivity to a drug and is believed to play a role in the etiology of substance use disorders. The purpose of the present study was to evaluate the ability of the mixed mu/kappa agonist nalbuphine to modulate sensitization to the locomotor and positive reinforcing effects of cocaine. Rats were habituated to a locomotor activity chamber and treated with saline (1.0 ml/kg, ip), cocaine (10 mg/kg, ip), or cocaine+nalbuphine (10 mg/kg, ip) every day for 10 days. Following locomotor activity testing, rats were implanted with intravenous catheters and cocaine self-administration was examined on fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement. Rats treated with cocaine exhibited a progressive increase in locomotor activity over the 10-day treatment period, and this effect was significantly reduced in rats treated with cocaine+nalbuphine. In self-administration tests, rats treated with cocaine exhibited significantly higher levels of responding at a threshold dose of cocaine (0.03 mg/kg/infusion) on both FR and PR schedules than rats treated with saline. This increase in responding at a threshold dose of cocaine was blocked completely in rats treated with cocaine+nalbuphine. These data suggest that nalbuphine attenuates the development of sensitization to the behavioral effects of cocaine.

Novel opioid cyclic tetrapeptides: Trp isomers of CJ-15,208 exhibit distinct opioid receptor agonism and short-acting κ opioid receptor antagonism

BACKGROUND AND PURPOSE

The κ opioid receptor antagonists demonstrate potential for maintaining abstinence from psychostimulant abuse, but existing non-peptide κ-receptor selective antagonists show exceptionally long activity. We hypothesized that the L- and D-Trp isomers of CJ-15,208, a natural cyclic tetrapeptide reported to be a κ-receptor antagonist in vitro, would demonstrate short-acting, dose-dependent antagonism in vivo, preventing reinstatement of cocaine-seeking behaviour.

EXPERIMENTAL APPROACH

Affinity, selectivity and efficacy of the L-Trp and D-Trp isomers for opioid receptors were assessed in vitro in radioligand and GTPγS binding assays. Opioid receptor agonist and antagonist activities were characterized in vivo following i.c.v. administration with the 55°C warm water tail-withdrawal assay. The D-Trp isomer, which demonstrated primarily κ-receptor selective antagonist activity, was further evaluated for its prevention of stress- and drug-induced reinstatement of extinguished cocaine conditioned place preference (CPP).

KEY RESULTS

The two isomers showed similar affinity and selectivity for κ receptors (K(i)  30-35 nM) as well as κ receptor antagonism in vitro. As expected, the D-Trp cyclic tetrapeptide exhibited minimal agonist activity and induced dose-dependent κ-receptor selective antagonism lasting less than 18 h in vivo. Pretreatment with this peptide prevented stress-, but not cocaine-induced, reinstatement of extinguished cocaine CPP. In contrast, the L-Trp cyclic tetrapeptide unexpectedly demonstrated mixed opioid agonist/antagonist activity.

CONCLUSIONS AND IMPLICATIONS

The L-Trp and the D-Trp isomers of CJ-15,208 demonstrate stereospecific opioid activity in vivo. The relatively brief κ opioid receptor antagonism, coupled with the prevention of stress-induced reinstatement of extinguished cocaine-seeking behaviour, suggests the D-Trp isomer could be used therapeutically to maintain abstinence from psychostimulant abuse.

Reconsidering anhedonia in depression: lessons from translational neuroscience

Anhedonia is a core symptom of major depressive disorder (MDD), the neurobiological mechanisms of which remain poorly understood. Despite decades of speculation regarding the role of dopamine (DA) in anhedonic symptoms, empirical evidence has remained elusive, with frequent reports of contradictory findings. In the present review, we argue that this has resulted from an underspecified definition of anhedonia, which has failed to dissociate between consummatory and motivational aspects of reward behavior. Given substantial preclinical evidence that DA is involved primarily in motivational aspects of reward, we suggest that a refined definition of anhedonia that distinguishes between deficits in pleasure and motivation is essential for the purposes of identifying its neurobiological substrates. Moreover, bridging the gap between preclinical and clinical models of anhedonia may require moving away from the conceptualization of anhedonia as a steady-state, mood-like phenomena. Consequently, we introduce the term "decisional anhedonia" to address the influence of anhedonia on reward decision-making. These proposed modifications to the theoretical definition of anhedonia have implications for research, assessment and treatment of MDD.

MDMA ("ecstasy") abuse as an example of dopamine neuroplasticity

A number of reviews have focused on the short- and long-term effects of MDMA and, in particular, on the persistent deficits in serotonin neurotransmission that accompany some exposure regimens. The mechanisms underlying the serotonin deficits and their relevance to various behavioral and cognitive consequences of MDMA use are still being debated. It has become clear, however, that some individuals develop compulsive and uncontrolled drug-taking that is consistent with abuse. For other drugs of abuse, this transition has been attributed to neuroadaptations in central dopamine mechanisms that occur as a function of repeated drug exposure. A question remains as to whether similar neuroadaptations occur as a function of exposure to MDMA and the impact of serotonin neurotoxicity in the transition from use to abuse. This review focuses specifically on this issue by first providing an overview of human studies and then reviewing the animal literature with specific emphasis on paradigms that measure subjective effects of drugs and self-administration as indices of abuse liability. It is suggested that serotonin deficits resulting from repeated exposure to MDMA self-administration lead to a sensitized dopaminergic response to the drug and that this sensitized response renders MDMA comparable to other drugs of abuse.

Effects of ATPM-ET, a novel κ agonist with partial μ activity, on physical dependence and behavior sensitization in mice

AIM

to investigate the effects of ATPM-ET [(-)-3-N-Ethylaminothiazolo [5,4-b]-N-cyclopropylmethylmorphinan hydrochloride] on physical dependence and behavioral sensitization to morphine in mice.

METHODS

the pharmacological profile of ATPM-ET was characterized using competitive binding and GTPγS binding assays. We then examined the antinociceptive effects of ATPM-ET in the hot plate test. Morphine dependence assay and behavioral sensitization assay were used to determine the effect of ATPM-ET on physical dependence and behavior sensitization to morphine in mice.

RESULTS

the binding assay indicated that ATPM-ET ATPM-ET exhibited a high affinity to both κ- and μ-opioid receptors with K(i) values of 0.15 nmol/L and 4.7 nmol/L, respectively, indicating it was a full κ-opioid receptor agonist and a partial μ-opioid receptor agonist. In the hot plate test, ATPM-ET produced a dose-dependent antinociceptive effect, with an ED(50) value of 2.68 (2.34-3.07) mg/kg. Administration of ATPM-ET (1 and 2 mg/kg, sc) prior to naloxone (3.0 mg/kg, sc) injection significantly inhibited withdrawal jumping of mice. In addition, ATPM-ET (1 and 2 mg/kg, sc) also showed a trend toward decreasing morphine withdrawal-induced weight loss. ATPM-ET (1.5 and 3 mg/kg, sc) 15 min before the morphine challenge significantly inhibited the morphine-induced behavior sensitization (P<0.05).

CONCLUSION

ATPM-ET may have potential as a therapeutic agent for the treatment of drug abuse.

Donepezil treatment and the subjective effects of intravenous cocaine in dependent individuals

Acetylcholinesterase (AChE) inhibitors increase synaptic levels of acetylcholine (ACh) by inhibiting its breakdown. Donepezil is a reversible AChE inhibitor that is clinically available and relatively selective for inhibiting AChE but not other cholinesterases. Because AChE inhibitors have been shown to decrease the reinforcing effects of cocaine in animals, our hypothesis was that pretreatment with donepezil would attenuate the perceived value and other positive subjective effects of cocaine. We conducted a within-subject, double-blind, placebo-controlled, laboratory-based evaluation of the subjective effects produced by intravenous cocaine in human subjects receiving oral donepezil. Following three days of daily treatment with 5mg of donepezil or oral placebo, participants received intravenous placebo or cocaine (0.18 and 0.36 mg/kg). After a three-day washout period, participants were crossed over to the opposite oral treatment, which was followed by identical intravenous infusions. Donepezil was well-tolerated with only two drug-related adverse events reported that were mild and self-limiting. Treatment with donepezil increased ratings of 'any' and 'good' drug effect produced by low-dose cocaine, without modifying the response to high-dose cocaine. When collapsed across intravenous dose, treatment with donepezil decreased dysphoric effects and somatic symptoms, but did not modify the value of cocaine injections as determined by the Multiple Choice Questionnaire (MCQ). In summary, pretreatment with donepezil potentiated some measures for nonspecific and positive effects of low-dose cocaine. Across all intravenous treatments, participants receiving donepezil reported fewer somatic-dysphoric effects. Neither of these actions support the value of donepezil as a treatment for cocaine dependence.

Opioid and cocaine combined effect on cocaine-induced changes in HPA and HPG axes hormones in men

Nalbuphine, a mixed micro-/kappa-opioid analgesic, may have potential as a new medication for the treatment of cocaine abuse. Kappa-opioid agonists functionally antagonize some abuse-related and locomotor effects of cocaine, and both kappa-selective and mixed micro-/kappa-opioids reduce cocaine self-administration by rhesus monkeys. Because cocaine's interactions with the hypothalamic-pituitary-adrenal and (HPA) hypothalamic-pituitary-gonadal (HPG) axes may contribute to its reinforcing properties, we examined the effects of cocaine alone and in combination with nalbuphine. Neuroendocrine effects of a single dose of cocaine alone (0.2 mg/kg, IV), with nalbuphine (5 mg/70 kg, IV)+cocaine (0.2 mg/kg, IV) in combination were compared in seven adult men (ages 18-35) who met DSM-IV criteria for current cocaine abuse. Cocaine alone, and in combination with nalbuphine was administered on separate test days under placebo-controlled, double blind conditions. Cocaine stimulated ACTH, cortisol, and LH, whereas cocaine+nalbuphine in combination produced a smaller increase in ACTH, and decreased cortisol and LH. Thus it appears that nalbuphine attenuated cocaine's effects on ACTH, cortisol, and LH. These data are consistent with our earlier report that nalbuphine modestly attenuated cocaine's positive subjective effects, and that the subjective and cardiovascular effects of cocaine+nalbuphine in combination were not additive.

Effects of kappa opioid agonists alone and in combination with cocaine on heart rate and blood pressure in conscious squirrel monkeys

As kappa agonists have been proposed as treatments for cocaine abuse, the cardiovascular effects of the kappa opioid receptor agonists ethylketocyclazocine (EKC) and enadoline were investigated in conscious squirrel monkeys. Both EKC and enadoline increased heart rate with little effect on blood pressure. This effect appeared to be specific for kappa receptors as the mu opioid agonist morphine did not mimic the effects of the kappa agonists. The opioid antagonist naltrexone, at a dose of 1.0 mg/kg, blocked the effect of EKC. An action at both central and peripheral receptors may be responsible for the heart rate increase following kappa agonist treatment. The ganglionic blocker chlorisondamine partially antagonized the effect of EKC on heart rate, suggesting central involvement, while the peripherally-acting agonist ICI 204,448 ((+/-)-1-[2,3- (Dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride) also increased heart rate, supporting a peripheral site of action. When given in combination with cocaine, EKC produced effects that were sub-additive, suggesting that the kappa agonists may be used safely as cocaine abuse treatments.

Effects of nalbuphine on anterior pituitary and adrenal hormones and subjective responses in male cocaine abusers

Nalbuphine (Nubain) is a mixed action mu-kappa agonist used clinically for the management of pain. Nalbuphine and other mu-kappa agonists decreased cocaine self-administration in preclinical models. Cocaine stimulates the hypothalamic-pituitary-adrenal (HPA) axis, but the effects of nalbuphine on the HPA axis are unknown. Analgesic doses (5 and 10 mg/70 kg) of IV nalbuphine were administered to healthy male cocaine abusers, and plasma levels of PRL, ACTH and cortisol were measured before and at 10, 17, 19, 23, 27, 31, 35, 40, 45, 60, 75, 105, and 135 min after nalbuphine administration. Subjective effects were measured on a Visual Analog Scale (VAS). Prolactin (PRL) increased significantly within 17 min (P=.04) and reached peak levels of 22.1+/-7.1 ng/ml and 54.1+/-11.3 at 60 min after low and high dose nalbuphine administration, respectively. VAS reports of "Sick," "Bad" and "Dizzy" were significantly higher after 10 mg/70 kg than after 5 mg/70 kg nalbuphine (P=.05-.0001), and were significantly correlated with increases in PRL (P=.05-.0003). However, sedation and emesis were observed only after a 10 mg/70 kg dose of nalbuphine. Interestingly, ACTH and cortisol levels did not change significantly after administration of either dose of nalbuphine. Taken together, these data suggest that nalbuphine had both mu- and kappa-like effects on PRL (PRL increase) but did not increase ACTH and cortisol.

Endogenous opiates and behavior: 2005

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).